source
stringclasses
1 value
problem
stringlengths
53
2.01k
solution
stringlengths
732
6.8k
messages
listlengths
2
2
olympiads
The founder of a noble family received a plot of land. Each man in the family, upon his death, divided the land equally among his sons. If a man had no sons, the land was transferred to the state. No other family members gained or lost land in any other way. There were a total of 180 people in the family. What is the s...
Let's consider a problem where each male in a noble family divides his land equally among his sons upon death. If a person has no sons, his land reverts to the state. Given there are 180 members in the family, we need to find the smallest share of the original land that any member could inherit. 1. **Understanding th...
[ { "content": "The founder of a noble family received a plot of land. Each man in the family, upon his death, divided the land equally among his sons. If a man had no sons, the land was transferred to the state. No other family members gained or lost land in any other way. There were a total of 180 people in the...
olympiads
Determine the values of \(\lambda\) for which the function $$ y=\frac{x^{2}-6 x+5}{x^{2}+4 x+\lambda} $$ does not have any extrema. Examine the behavior of this function and plot it for \(\lambda = -12\).
1. **Understanding Function Properties and Differentiability:** Given the function \[ y = \frac{x^2 - 6x + 5}{x^2 + 4x + \lambda} \] we need to determine the values of \(\lambda\) for which the function does not have any extremum (neither maximum nor minimum). 2. **Condition for No Extremum:** ...
[ { "content": "Determine the values of \\(\\lambda\\) for which the function\n\n$$\ny=\\frac{x^{2}-6 x+5}{x^{2}+4 x+\\lambda}\n$$\n\ndoes not have any extrema. Examine the behavior of this function and plot it for \\(\\lambda = -12\\).", "role": "user" }, { "content": "\n1. **Understanding Function P...
olympiads
For a positive integer \( n \geq 3 \), plot \( n \) equally spaced points around a circle. Label one of them \( A \), and place a marker at \( A \). One may move the marker forward in a clockwise direction to either the next point or the point after that. Hence there are a total of \( 2n \) distinct moves available; tw...
We will present the solution in a detailed step-by-step manner, referencing the initial problem statement and ensuring all necessary justifications are provided. **First solution:** 1. **Problem Setup:** We will consider $n$ equally spaced points labeled $0, 1, 2, \ldots, n-1$ placed around a circle. We are t...
[ { "content": "For a positive integer \\( n \\geq 3 \\), plot \\( n \\) equally spaced points around a circle. Label one of them \\( A \\), and place a marker at \\( A \\). One may move the marker forward in a clockwise direction to either the next point or the point after that. Hence there are a total of \\( 2n...
olympiads
A rectangular plot for rye cultivation was modified: one side was increased by 20%, while the other side was decreased by 20%. Will the rye yield change as a result, and if so, by how much?
1. Let \(a\) and \(b\) be the original sides of the rectangular field. 2. After the restructuring, one side of the rectangle is increased by \(20\%\) and the other side is decreased by \(20\%\). - Increasing \(a\) by \(20\%\) means the new length is: \[ a_{\text{new}} = 1.2a \] - Decreasing \...
[ { "content": "A rectangular plot for rye cultivation was modified: one side was increased by 20%, while the other side was decreased by 20%. Will the rye yield change as a result, and if so, by how much?", "role": "user" }, { "content": "1. Let \\(a\\) and \\(b\\) be the original sides of the rectan...
olympiads
The cost of traveling on a toll road section depends on the vehicle class: passenger cars belong to the first class, for which the travel cost is 200 rubles, while light trucks and minibuses belong to the second class, for which the cost is 300 rubles. At the toll payment point, an automatic system is installed which...
1. **Problem Restatement**: We need to find the optimal threshold value \( h \) for an automated toll system that minimizes the classification errors for vehicles passing through a toll booth. Vehicles are classified into two classes based on their height: - Class 1: Heights less than \( h \), costing 20...
[ { "content": "\nThe cost of traveling on a toll road section depends on the vehicle class: passenger cars belong to the first class, for which the travel cost is 200 rubles, while light trucks and minibuses belong to the second class, for which the cost is 300 rubles.\n\nAt the toll payment point, an automatic ...
olympiads
Plot the solution set of the system of equations \(\left\{\begin{array}{l} x - 2y = 1 \\ x^{3} - 6xy - 8y^{3} = 1 \end{array}\right.\) on the coordinate plane.
1. **Given system of equations**: \[ \begin{cases} x - 2y = 1 \\ x^3 - 6xy - 8y^3 = 1 \end{cases} \] 2. **Rewriting the first equation**: Given: \[ x - 2y = 1 \] We can express \(x\) in terms of \(y\): \[ x = 2y + 1 \] 3. **Substituting \(x = 2y + 1\) into the second equati...
[ { "content": "Plot the solution set of the system of equations \\(\\left\\{\\begin{array}{l} x - 2y = 1 \\\\ x^{3} - 6xy - 8y^{3} = 1 \\end{array}\\right.\\) on the coordinate plane.", "role": "user" }, { "content": "\n1. **Given system of equations**:\n \\[\n \\begin{cases}\n x - 2y = 1 \\\\\...
olympiads
Plot the solution set of the system of equations \(\left\{\begin{array}{l} x - 2y = 1 \\ x^{3} - 6xy - 8y^{3} = 1 \end{array}\right.\) on the coordinate plane.
1. **Given system of equations**: \[ \begin{cases} x - 2y = 1 \\ x^3 - 6xy - 8y^3 = 1 \end{cases} \] 2. **Rewriting the first equation**: Given: \[ x - 2y = 1 \] We can express \(x\) in terms of \(y\): \[ x = 2y + 1 \] 3. **Substituting \(x = 2y + 1\) into the second equati...
[ { "content": "Plot the solution set of the system of equations \\(\\left\\{\\begin{array}{l} x - 2y = 1 \\\\ x^{3} - 6xy - 8y^{3} = 1 \\end{array}\\right.\\) on the coordinate plane.", "role": "user" }, { "content": "\n1. **Given system of equations**:\n \\[\n \\begin{cases}\n x - 2y = 1 \\\\\...
olympiads
On both sides of a 1200 m long street, there are rectangular strips of land designated for plots, one with a width of 50 m and the other with a width of 60 m. How many plots is the entire village divided into if the narrower strip contains 5 more plots than the wider strip, given that each plot on the narrower strip is...
1. Let's denote the number of plots on the wide strip as \( x \), and the number of plots on the narrow strip as \( x + 5 \). 2. We are additionally given that each plot on the narrow strip is 1200 square meters smaller than each plot on the wide strip. 3. Let \( y \) be the area of one plot on the narrow strip, th...
[ { "content": "On both sides of a 1200 m long street, there are rectangular strips of land designated for plots, one with a width of 50 m and the other with a width of 60 m. How many plots is the entire village divided into if the narrower strip contains 5 more plots than the wider strip, given that each plot on...
olympiads
Let \( n \) be a positive integer. Roger has a \( (2n+1) \times (2n+1) \) square garden. He puts down fences to divide his garden into rectangular plots. He wants to end up with exactly two horizontal \( k \times 1 \) plots and exactly two vertical \( 1 \times k \) plots for each even integer \( k \) between 1 and \( 2...
We are asked to determine the number of ways Roger can divide his \((2n+1) \times (2n+1)\) garden such that it contains exactly two horizontal \(k \times 1\) plots, two vertical \(1 \times k\) plots for each even integer \(k \in [2, 2n+1]\), and a single \(1 \times 1\) plot. Let's consider the problem step-by-step. ...
[ { "content": "Let \\( n \\) be a positive integer. Roger has a \\( (2n+1) \\times (2n+1) \\) square garden. He puts down fences to divide his garden into rectangular plots. He wants to end up with exactly two horizontal \\( k \\times 1 \\) plots and exactly two vertical \\( 1 \\times k \\) plots for each even i...
olympiads
A farmer fenced an outside plot of land and divided it into triangles with sides measuring 50 meters. In some of the triangles, he planted cabbage, while in others, he allowed goats to graze. Help the farmer to build additional fences along the grid lines with the shortest total length possible to protect all the cabba...
1. **Objective Clarification** The problem requires us to construct fences along the lines of a triangular grid to protect cabbage from goats. The goal is to use the minimum total fence length. The triangular grid consists of triangles with sides of 50 meters each. 2. **Initial Observation** The solution illus...
[ { "content": "A farmer fenced an outside plot of land and divided it into triangles with sides measuring 50 meters. In some of the triangles, he planted cabbage, while in others, he allowed goats to graze. Help the farmer to build additional fences along the grid lines with the shortest total length possible to...
olympiads
On a rectangular plot, a house is being built. In a right-angled coordinate system defined by two adjacent sides of the plot, the coordinates of two adjacent corners of the house are: $(1 ; 14),(17 ; 2)$. Where should the other two corners of the house be staked out if they want the shorter walls of the house to be hal...
### Problem: On a rectangular lot, a house is being built. In a right-angle coordinate system defined by two adjacent sides of the lot, the coordinates of two adjacent corners of the house are given as \((1; 14)\) and \((17; 2)\). Where should the other two corners of the house be marked if it is desired that the shor...
[ { "content": "On a rectangular plot, a house is being built. In a right-angled coordinate system defined by two adjacent sides of the plot, the coordinates of two adjacent corners of the house are: $(1 ; 14),(17 ; 2)$. Where should the other two corners of the house be staked out if they want the shorter walls ...
olympiads
On a rectangular plot measuring $5 \times 6$ meters, there is a triangular flower bed. Find the area of this flower bed (in square meters).
1. The rectangular plot has dimensions \(5 \, \text{m} \times 6 \, \text{m}\). First, calculate the area of the entire plot: \[ \text{Area of the plot} = 5 \, \text{m} \times 6 \, \text{m} = 30 \, \text{m}^2 \] 2. Next, identify the areas of the two triangular parts that are not occupied by the triangular flo...
[ { "content": "On a rectangular plot measuring $5 \\times 6$ meters, there is a triangular flower bed. Find the area of this flower bed (in square meters).", "role": "user" }, { "content": "1. The rectangular plot has dimensions \\(5 \\, \\text{m} \\times 6 \\, \\text{m}\\). First, calculate the area...
olympiads
At 2 p.m., Sanjay measures the temperature to be \(3^{\circ} \mathrm{C}\). He measures the temperature every hour after this until 10 p.m. He plots the temperatures that he measures on the graph shown. At what time after 2 p.m. does he again measure a temperature of \(3^{\circ} \mathrm{C}\)? (A) 9 p.m. (B) 5 p.m. (C) ...
1. **Identify the Relevant Temperature Line**: - The problem requires identifying the time at which the temperature is measured again at \(3^{\circ} \, \mathrm{C}\). - On the vertical axis, locate the horizontal line passing halfway between \(2^{\circ} \, \mathrm{C}\) and \(4^{\circ} \, \mathrm{C}\). This line r...
[ { "content": "At 2 p.m., Sanjay measures the temperature to be \\(3^{\\circ} \\mathrm{C}\\). He measures the temperature every hour after this until 10 p.m. He plots the temperatures that he measures on the graph shown. At what time after 2 p.m. does he again measure a temperature of \\(3^{\\circ} \\mathrm{C}\\...
olympiads
Find the number of all trees planted at a five-foot distance from each other on a rectangular plot of land, the sides of which are 120 feet and 70 feet.
To solve the problem of finding the number of trees planted at 5-foot intervals on a rectangular plot of land with sides of 120 feet and 70 feet, we will follow these steps: 1. **Determine the number of intervals along the length and width of the plot:** Since the trees are planted 5 feet apart, we can find the n...
[ { "content": "Find the number of all trees planted at a five-foot distance from each other on a rectangular plot of land, the sides of which are 120 feet and 70 feet.", "role": "user" }, { "content": "\nTo solve the problem of finding the number of trees planted at 5-foot intervals on a rectangular ...
olympiads
A farmer fenced off a plot of land and divided it into triangles with sides of $50 \mathrm{~m}$. In some triangles, he planted cabbage, while in others, he let goats graze. Help the farmer build additional fences along the grid lines with the smallest possible total length to protect all the cabbage from the goats.
To solve this problem and construct additional fences of minimal total length to protect all the cabbage from the goats, follow these steps: 1. **Understanding the Setup:** - The farmer has divided the land into equilateral triangles with each side measuring \(50 \mathrm{~m}\). - Some triangles have cabbage, an...
[ { "content": "A farmer fenced off a plot of land and divided it into triangles with sides of $50 \\mathrm{~m}$. In some triangles, he planted cabbage, while in others, he let goats graze. Help the farmer build additional fences along the grid lines with the smallest possible total length to protect all the cabb...
olympiads
Given the probability densities of two independent uniformly distributed random variables $X$ and $Y$: $f_{1}(x)=\frac{1}{2}$ in the interval $(0, 2)$, outside this interval $f_{1}(x)=0$ $f_{2}(y)=\frac{1}{2}$ in the interval $(0, 2)$, outside this interval $f_{2}(y)=0$ Find the cumulative distribution function (CDF...
1. **Given Information and Definitions:** The densities of uniformly distributed independent random variables \(X\) and \(Y\) are given as: \[ f_{1}(x) = \begin{cases} \frac{1}{2} & 0 < x < 2 \\ 0 & \text{otherwise} \end{cases} \] \[ f_{2}(y) = \begin{cases} \frac{1...
[ { "content": "Given the probability densities of two independent uniformly distributed random variables $X$ and $Y$:\n\n$f_{1}(x)=\\frac{1}{2}$ in the interval $(0, 2)$, outside this interval $f_{1}(x)=0$\n\n$f_{2}(y)=\\frac{1}{2}$ in the interval $(0, 2)$, outside this interval $f_{2}(y)=0$\n\nFind the cumulat...
olympiads
A square plot measuring 14 by 14 cells needs to be paved with rectangular tiles sized 1 by 4. The tiles can only be laid along the grid (not diagonally), and tiles cannot be broken. What is the maximum number of tiles required? Will there be any unpaved area left?
1. **Calculate the total number of cells in the grid:** The given grid is a square of size \(14 \text{ by } 14\). \[ 14 \times 14 = 196 \] Therefore, there are 196 cells in total. 2. **Determine the number of tiles needed:** Each tile is of size \(1 \text{ by } 4\), so it covers 4 cells. \[ \f...
[ { "content": "A square plot measuring 14 by 14 cells needs to be paved with rectangular tiles sized 1 by 4. The tiles can only be laid along the grid (not diagonally), and tiles cannot be broken. What is the maximum number of tiles required? Will there be any unpaved area left?", "role": "user" }, { ...
olympiads
In the 6 plots of land shown in Figure 3-11, plant either type A or type B vegetables (you can plant only one type or both). The requirement is that two adjacent plots should not both have type A vegetables. Determine the total number of possible planting schemes.
1. **Understanding the constraints and setup**: We have 6 plots of land where we can plant two types of vegetables, labeled as type "A" and type "B". The problem states that no two adjacent plots can both have type "A" vegetables. 2. **Identify the maximum number of type "A" vegetables we can plant**: - Given the ...
[ { "content": "In the 6 plots of land shown in Figure 3-11, plant either type A or type B vegetables (you can plant only one type or both). The requirement is that two adjacent plots should not both have type A vegetables. Determine the total number of possible planting schemes.", "role": "user" }, { ...
olympiads
When land plots were being allocated, farmer Novoselov was assigned 2 square plots of different areas with integer side lengths. Is it possible to assign farmer Malinnikov 2 square plots with integer side lengths such that the total area of Malinnikov's plots is 2 times greater than the total area of Novoselov's plots?
1. Denote the sides of the squares allocated to farmer Novoselov as \( x \) and \( y \) such that \( x > y \). - Hence, the areas of these squares are \( x^2 \) and \( y^2 \). 2. The total area of the squares allocated to Novoselov is: \[ a = x^2 + y^2 \] 3. According to the problem, the total area of th...
[ { "content": "When land plots were being allocated, farmer Novoselov was assigned 2 square plots of different areas with integer side lengths. Is it possible to assign farmer Malinnikov 2 square plots with integer side lengths such that the total area of Malinnikov's plots is 2 times greater than the total area...
olympiads
In the school campus, there is a rectangular plot that is 18 meters long and 12 meters wide. The plan is to plant red flowers, yellow flowers, and green grass. According to one design plan, what is the area of the red flowers in square meters?
1. Determine the total area of the rectangular plot: \[ \text{Total area} = \text{length} \times \text{width} = 18 \, \text{meters} \times 12 \, \text{meters} = 216 \, \text{square meters} \] 2. According to the problem, the area for red flowers and yellow flowers together forms half of the total area of ...
[ { "content": "In the school campus, there is a rectangular plot that is 18 meters long and 12 meters wide. The plan is to plant red flowers, yellow flowers, and green grass. According to one design plan, what is the area of the red flowers in square meters?", "role": "user" }, { "content": "\n1. Det...
olympiads
In the town of Oropis, there is a lake in the shape of a triangle with each of the three sides being part of the perimeter of a square plot, with areas $370 \mathrm{~m}^{2}, 116 \mathrm{~m}^{2},$ and $74 \mathrm{~m}^{2}$, as shown in the first figure. The mayor of Oropis, Arnaldo, wants to calculate the area of the lak...
#### (a) Determine valores inteiros de \( a, b, c \) e \( d \) que satisfaçam as condições geométricas da figura de Bernaldo. We are given a series of geometric constraints based on the areas: \[ \begin{aligned} a^2 + c^2 &= 74 \\ b^2 + d^2 &= 116 \\ (a + b)^2 + (c + d)^2 &= 370 \end{aligned} \] To solve for the in...
[ { "content": "In the town of Oropis, there is a lake in the shape of a triangle with each of the three sides being part of the perimeter of a square plot, with areas $370 \\mathrm{~m}^{2}, 116 \\mathrm{~m}^{2},$ and $74 \\mathrm{~m}^{2}$, as shown in the first figure. The mayor of Oropis, Arnaldo, wants to calc...
olympiads
Find such \( n \) and such numbers \( a_{i}, b_{i}, c_{i} \) \((i=1,2, \ldots, n)\) that the condition \[ \sum_{i=1}^{n}\left|a_{i} x+b_{i} y+c_{i}\right|=10 \] is satisfied, such that the pairs \((x, y)\) plotted in the coordinate system form the points of a regular octagon.
1. We need to find a value of \( n \) and numbers \( a_{i}, b_{i}, c_{i} \) for \( i=1,2, \ldots, n \) such that the condition \[ \sum_{i=1}^{n} \left|a_{i} x + b_{i} y + c_{i}\right| = 10 \] is satisfied by the coordinates of the vertices of a regular octagon when plotted on the coordinate system. 2. L...
[ { "content": "Find such \\( n \\) and such numbers \\( a_{i}, b_{i}, c_{i} \\) \\((i=1,2, \\ldots, n)\\) that the condition\n\n\\[ \n\\sum_{i=1}^{n}\\left|a_{i} x+b_{i} y+c_{i}\\right|=10 \n\\]\n\nis satisfied, such that the pairs \\((x, y)\\) plotted in the coordinate system form the points of a regular octago...
olympiads
Investigate the function \( y = \ln \left| \frac{x-1}{x+1} \right| \) and plot its graph.
1. **Identify the Domain**: The function \(y = \ln \left| \frac{x-1}{x+1} \right|\) is undefined when the argument of the natural logarithm is non-positive. Specifically, the function is not defined at \(x = -1\) and \(x = 1\). Therefore, the domain of the function consists of the intervals \( (-\infty, -1) \),...
[ { "content": "Investigate the function \\( y = \\ln \\left| \\frac{x-1}{x+1} \\right| \\) and plot its graph.", "role": "user" }, { "content": "\n1. **Identify the Domain**:\n The function \\(y = \\ln \\left| \\frac{x-1}{x+1} \\right|\\) is undefined when the argument of the natural logarithm is n...
olympiads
In triangle \( ABC \), point \( D \) is the midpoint of side \( AB \), \( E \) is the midpoint of side \( AC \), and \( F \) is the midpoint of the bisector \( AL \). Given that \( D F = 1 \) and \( E F = 2 \). Points \( D \), \( E \), and \( F \) are plotted on a plane such that line \( DF \) is horizontal, and the ot...
#### Step 1: Establish basic conditions In a triangle $ABC$: - Point $D$ is the midpoint of side $AB$. - Point $E$ is the midpoint of side $AC$. - Point $F$ is the midpoint of the bisector $AL$ of angle $A$. Given: \[ DF = 1 \quad \text{and} \quad EF = 2 \] #### Step 2: Visualize the configuration We are given that ...
[ { "content": "In triangle \\( ABC \\), point \\( D \\) is the midpoint of side \\( AB \\), \\( E \\) is the midpoint of side \\( AC \\), and \\( F \\) is the midpoint of the bisector \\( AL \\). Given that \\( D F = 1 \\) and \\( E F = 2 \\). Points \\( D \\), \\( E \\), and \\( F \\) are plotted on a plane suc...
olympiads
A rectangular plot was allocated for a sports field, with a diagonal measuring 185 meters. During construction, the length of each side was reduced by 4 meters, maintaining the rectangular shape, but the area was reduced by $1012 \mathrm{~m}^{2}$. What are the actual dimensions of the sports field?
1. Let \( x \) be the length and \( y \) the width of the original rectangular plot. According to the Pythagorean Theorem, we have: \[ x^2 + y^2 = 185^2 \] \[ x^2 + y^2 = 34225 \] 2. Both the length and width were reduced by 4 meters, thus the new dimensions are \( x - 4 \) and \( y - 4 \). The ar...
[ { "content": "A rectangular plot was allocated for a sports field, with a diagonal measuring 185 meters. During construction, the length of each side was reduced by 4 meters, maintaining the rectangular shape, but the area was reduced by $1012 \\mathrm{~m}^{2}$. What are the actual dimensions of the sports fiel...
olympiads
Remove the highest and lowest scores out of nine scores of a certain contestant. The average of the remaining seven scores is 91. In the stem-and-leaf plot of the nine scores, one score is unclear and is represented as $x$ in Figure 1. What is the variance of the remaining seven scores? (A) $\frac{116}{9}$ (B) $\fr...
1. Let's identify the provided points for the analysis: \[ 87, 87, 94, 90, 91, 90, 9x, 99, 91 \] 2. From the problem, we are given that the average score of the seven remaining scores (after removing the highest and lowest scores) is \(91\). 3. Determine the highest and lowest scores from the provided data: \[...
[ { "content": "Remove the highest and lowest scores out of nine scores of a certain contestant. The average of the remaining seven scores is 91. In the stem-and-leaf plot of the nine scores, one score is unclear and is represented as $x$ in Figure 1. What is the variance of the remaining seven scores? \n\n(A) $\...
olympiads
A rectangular plot has a length of 4 meters and a width of 1 meter. Is it possible to plant three trees on it so that the distance between any two trees is at least 2.5 meters?
1. **Define the dimensions of the rectangular plot**: - Length: \(4\) meters - Width: \(1\) meter. 2. **Setting up the problem**: - We need to determine if it is possible to plant three trees on this plot such that the distance between any two trees is at least \(2.5\) meters. 3. **Divide the rectangular p...
[ { "content": "A rectangular plot has a length of 4 meters and a width of 1 meter.\n\nIs it possible to plant three trees on it so that the distance between any two trees is at least 2.5 meters?", "role": "user" }, { "content": "\n1. **Define the dimensions of the rectangular plot**:\n - Length: \\...
olympiads
As shown in the figure, Rourou's vegetable garden consists of 4 square plots and 1 small rectangular pool forming a large rectangle. If the area of each plot is 20 square meters and the garden's length is 10 meters, what is the perimeter of the pool (the shaded area in the figure) in meters?
1. **Analyzing the given data:** - There are 4 squares and 1 small rectangle forming a larger rectangle. - Each square has an area of 20 square meters. - The length of the garden (entire large rectangle) is given as 10 meters. 2. **Finding the dimensions of each square:** Since each square has an area o...
[ { "content": "As shown in the figure, Rourou's vegetable garden consists of 4 square plots and 1 small rectangular pool forming a large rectangle. If the area of each plot is 20 square meters and the garden's length is 10 meters, what is the perimeter of the pool (the shaded area in the figure) in meters?", ...
olympiads
Plot on the $(x, y)$ plane the set of points whose coordinates satisfy the system: \[ \left\{ \begin{array}{l} (| x | + x)^{2} + (| y | + y)^{2} \leq 4, \\ 3y + x \leq 0 \end{array} \right. \]
We need to find the points \((x, y)\) on the coordinate plane that satisfy the system of inequalities: \[ \begin{cases} (|x| + x)^2 + (|y| + y)^2 \leq 4, \\ 3y + x \leq 0. \end{cases} \] Let's start by examining the first inequality, \((|x| + x)^2 + (|y| + y)^2 \leq 4\). Notice that the expression \((|x| + x)\) and ...
[ { "content": "Plot on the $(x, y)$ plane the set of points whose coordinates satisfy the system:\n\\[\n\\left\\{\n\\begin{array}{l}\n(| x | + x)^{2} + (| y | + y)^{2} \\leq 4, \\\\\n3y + x \\leq 0\n\\end{array}\n\\right.\n\\]", "role": "user" }, { "content": "\nWe need to find the points \\((x, y)\\...
olympiads
A plot of land is sown with seeds of smooth brome. On one section of this plot, weeds make up $0.4\%$ of the vegetation. What is the probability that among 125 plants randomly selected from this section, there are: a) exactly 3 weeds; b) no more than 3 weeds.
To solve the problem, we use the Poisson distribution, which is suitable here given that the number of trials is large ($n = 125$) and the probability of each individual event occurring is very small ($p = 0.004$). Thus, we approximate the binomial distribution using the Poisson distribution with $\lambda = np$. For ...
[ { "content": "A plot of land is sown with seeds of smooth brome. On one section of this plot, weeds make up $0.4\\%$ of the vegetation. What is the probability that among 125 plants randomly selected from this section, there are:\n\na) exactly 3 weeds;\n\nb) no more than 3 weeds.", "role": "user" }, { ...
olympiads
Given the vibrations \( y_{1} = \sin x \) and \( y_{2} = \sin^2 x \), study the properties of their combined motion \( y = y_{1} + y_{2} = \sin x + \sin^2 x \) (range of \( y \), maximum value, minimum value, zeros, variation, symmetry, periodicity, and plot the graph).
Given the function $y = y_1 + y_2 = \sin x + \sin^2 x$, we need to analyze its properties, including its value range, maximum and minimum values, zeros, variation, symmetry, periodicity, and plot its graph. 1. **Value Range, Maximum, and Minimum Values:** \[ y = \sin x + \sin^2 x \] To determine the ...
[ { "content": "Given the vibrations \\( y_{1} = \\sin x \\) and \\( y_{2} = \\sin^2 x \\), study the properties of their combined motion \\( y = y_{1} + y_{2} = \\sin x + \\sin^2 x \\) (range of \\( y \\), maximum value, minimum value, zeros, variation, symmetry, periodicity, and plot the graph).", "role": "...
olympiads
A father had three sons and left them an inheritance of 900 square meters of land - a rectangle measuring 25 m × 36 m. The brothers decided to divide the land into three rectangular plots of 300 square meters each. How many ways are there to divide it (in terms of the lengths and widths of the plots), and in which opti...
Given a rectangular plot of land with dimensions \(25 \, m \times 36 \, m\) or an area of \(900 \, m^2\), it needs to be divided into three rectangular sections such that each section has an area of \(3 \times 100 = 300 \, m^2\). We need to find how many ways this division can be made, and determine in which scenario ...
[ { "content": "A father had three sons and left them an inheritance of 900 square meters of land - a rectangle measuring 25 m × 36 m. The brothers decided to divide the land into three rectangular plots of 300 square meters each. How many ways are there to divide it (in terms of the lengths and widths of the plo...
olympiads
Simplify the expression \( y = \sqrt{x + 2 \sqrt{x - 1}} + \sqrt{x - 2 \sqrt{x - 1}} \), and then plot the graph of the function \( y \) for \( 1 \leq x < \infty \).
Let's simplify the given expression \( y = \sqrt{x + 2 \sqrt{x-1}} + \sqrt{x - 2 \sqrt{x-1}} \) step-by-step. 1. **Considering the domain of the expression:** \[ \text{For the expression to be real, the terms under the square root must be non-negative. Thus, } x - 1 \geq 0 \implies x \geq 1. \] Therefore,...
[ { "content": "Simplify the expression \\( y = \\sqrt{x + 2 \\sqrt{x - 1}} + \\sqrt{x - 2 \\sqrt{x - 1}} \\), and then plot the graph of the function \\( y \\) for \\( 1 \\leq x < \\infty \\).", "role": "user" }, { "content": "\nLet's simplify the given expression \\( y = \\sqrt{x + 2 \\sqrt{x-1}} + ...
olympiads
A rectangular plot of 800 square meters is to be fenced using 100 meters of fencing. What are the dimensions of the plot?
1. **Understanding the problem setup:** - We have a rectangular plot of land by a river with an area of \(800 \, \text{m}^2\). - We can only use \(100 \, \text{m}\) of fencing to enclose this plot. - Assume the rectangular plot is positioned such that one of its sides is along the river, which means this side...
[ { "content": "A rectangular plot of 800 square meters is to be fenced using 100 meters of fencing. What are the dimensions of the plot?", "role": "user" }, { "content": "\n1. **Understanding the problem setup:**\n - We have a rectangular plot of land by a river with an area of \\(800 \\, \\text{m}...
olympiads
Given the function \( f(x) = x^2 - 6x + 5 \), determine the region in the plane where the points \((x, y)\) satisfy both \( f(x) + f(y) \leq 0 \) and \( f(x) - f(y) \geq 0 \). Also, plot the graph of this region.
1. **Transform the constraint \( f(x) + f(y) \leq 0 \) into a geometric condition**: Given the function \( f(x) = x^2 - 6x + 5 \), we first compute \( f(x) \) at two different variables, \( x \) and \( y \). Thus, we have: \[ f(x) = x^2 - 6x + 5 \] \[ f(y) = y^2 - 6y + 5 \] Therefo...
[ { "content": "Given the function \\( f(x) = x^2 - 6x + 5 \\), determine the region in the plane where the points \\((x, y)\\) satisfy both \\( f(x) + f(y) \\leq 0 \\) and \\( f(x) - f(y) \\geq 0 \\). Also, plot the graph of this region.", "role": "user" }, { "content": "\n1. **Transform the constrai...
olympiads
Plot the graphs of the functions $$ y=\log_{3} x, \quad y=\log_{x} 3, \quad y=\log_{\frac{1}{3}} x, \quad y=\log_{x} \frac{1}{3} $$ on the same coordinate system. How many intersection points are there on the positive half of the x-axis? (A) 2 (B) 3 (C) 4 (D) 5 (E) 6
To solve the given problem, we need to analyze the functions and their intersections in the first quadrant ($x > 0$). The four logarithmic functions given are: 1. \( y = \log_{3} x \) 2. \( y = \log_{x} 3 \) 3. \( y = \log_{\frac{1}{3}} x \) 4. \( y = \log_{x} \frac{1}{3} \) Let's introduce a substitution to simplif...
[ { "content": "Plot the graphs of the functions \n$$\ny=\\log_{3} x, \\quad y=\\log_{x} 3, \\quad y=\\log_{\\frac{1}{3}} x, \\quad y=\\log_{x} \\frac{1}{3}\n$$\non the same coordinate system. How many intersection points are there on the positive half of the x-axis?\n\n(A) 2 \n(B) 3 \n(C) 4 \n(D) 5 \n(E) 6",...
olympiads
Upon returning from the collective farm garden, the boys were eagerly discussing the results of their work harvesting carrots. "What are the dimensions of the plot we were working on?" they asked their foreman, Vasya. "I lost the measurement records somewhere," he replied, "but I remember that the plot is square and it...
To find the length of the side of the field and its area, we need to determine the square integer value that lies within four digits and has all its digits even and distinct. Let's analyze step-by-step: 1. **Identify the Range of Possible Values:** - Since the field's area $A$ must be a four-digit number, we seek ...
[ { "content": "Upon returning from the collective farm garden, the boys were eagerly discussing the results of their work harvesting carrots. \"What are the dimensions of the plot we were working on?\" they asked their foreman, Vasya. \"I lost the measurement records somewhere,\" he replied, \"but I remember tha...
olympiads
Plot the points \( P(x, y) \) in the Cartesian coordinate system that satisfy the following inequality: $$ |x-1|+|x+1|+|2y| \leq 4. $$
To solve the inequality \(|x-1| + |x+1| + |2y| \leq 4\) and represent the solution set \(P(x, y)\) in the Cartesian plane, we need to account for the absolute value expressions by breaking the real number plane into several regions. Specifically, we will consider the following cases: 1. \( x \leq -1 \) 2. \(-1 < x \l...
[ { "content": "Plot the points \\( P(x, y) \\) in the Cartesian coordinate system that satisfy the following inequality:\n\n$$\n|x-1|+|x+1|+|2y| \\leq 4.\n$$", "role": "user" }, { "content": "\nTo solve the inequality \\(|x-1| + |x+1| + |2y| \\leq 4\\) and represent the solution set \\(P(x, y)\\) in ...
olympiads
The gardening association is a square \(8 \times 8\), divided into 64 equal square plots. Dandelions are growing on the plots. On one plot, there are 19 dandelions, and on another, there are 6. The number of dandelions on each plot differs from the number on any adjacent plot (i.e., a plot sharing a common side) by exa...
1. Consider the given problem, where we have an $8 \times 8$ square grid divided into 64 equal square plots, each plot having a different number of dandelions such that the number of dandelions on adjacent plots differs by exactly 1. We are given two specific plots with 19 and 6 dandelions respectively. 2. The goal is ...
[ { "content": "The gardening association is a square \\(8 \\times 8\\), divided into 64 equal square plots. Dandelions are growing on the plots. On one plot, there are 19 dandelions, and on another, there are 6. The number of dandelions on each plot differs from the number on any adjacent plot (i.e., a plot shar...
olympiads
Given the function \( f(x) = x^2 + x - 2 \). (1) Find the expression for the function \( g(x) = \frac{|f(x)| - f(x)}{2} \); (2) If for \( a > 0 \), the line \( y = ax + b \) intersects the curve \( y = g(x) \) at three distinct points, determine the relationship between \( a \) and \( b \), and plot the region of poi...
**Part 1: Find the analytical expression for \( g(x) = \frac{|f(x)| - f(x)}{2} \)** We are given the function \( f(x) = x^2 + x - 2 \). 1. Compute \( f(x) \): \[ f(x) = x^2 + x - 2 \] 2. Analyze the roots of \( f(x) \) to determine where \( f(x) \geq 0 \) and \( f(x) < 0 \). Solve \( f(x) = 0 \): \[...
[ { "content": "Given the function \\( f(x) = x^2 + x - 2 \\).\n\n(1) Find the expression for the function \\( g(x) = \\frac{|f(x)| - f(x)}{2} \\);\n\n(2) If for \\( a > 0 \\), the line \\( y = ax + b \\) intersects the curve \\( y = g(x) \\) at three distinct points, determine the relationship between \\( a \\) ...
olympiads
The perimeter of a triangle is \(12 \mathrm{~cm}\), and the length of one of its sides is \(5 \mathrm{~cm}\). Find the relationship between the lengths of the other two sides and plot the graph of this relationship.
1. Let the lengths of the three sides of the triangle be $a, b,$ and $c$. Given that one of the sides, say $a$, is $5 \text{ cm}$. 2. The perimeter of the triangle is given to be $12 \text{ cm}$. Therefore, we have the equation: \[ a + b + c = 12 \] Substituting $a = 5$, we get: \[ 5 + b + c = 12...
[ { "content": "The perimeter of a triangle is \\(12 \\mathrm{~cm}\\), and the length of one of its sides is \\(5 \\mathrm{~cm}\\). Find the relationship between the lengths of the other two sides and plot the graph of this relationship.", "role": "user" }, { "content": "\n1. Let the lengths of the th...
olympiads
A plot of 80 by 50 meters is allocated for gardens and fenced on the outside. How can 5 straight fences of the same length be placed inside the plot to divide it into 5 rectangular sections of equal area?
1. **Define the Problem Requirements:** We are given a rectangular plot of dimensions \(80 \, \text{meters} \times 50 \, \text{meters}\). We need to install 5 straight fences inside this plot such that they divide the area into 5 smaller rectangular areas of equal size. Each of these fences must be of the same len...
[ { "content": "A plot of 80 by 50 meters is allocated for gardens and fenced on the outside. How can 5 straight fences of the same length be placed inside the plot to divide it into 5 rectangular sections of equal area?", "role": "user" }, { "content": "\n1. **Define the Problem Requirements:**\n\n ...
olympiads
Three friends bought a square plot of land and want to divide it into three plots of equal area, as indicated in the figure, because in the corner of the plot marked by \( A \) there is a good water source. How far from the vertex \( C \) of the plot should the boundary points \( M \) and \( N \) indicated in the figur...
1. **Identify the Problem and Setup:** We are given a square piece of land where three friends want to divide it into three equal areas. Each portion should have the same area, and the division should be as indicated in the figure provided in the problem. The task is to determine the distance from vertex \(C\) to t...
[ { "content": "Three friends bought a square plot of land and want to divide it into three plots of equal area, as indicated in the figure, because in the corner of the plot marked by \\( A \\) there is a good water source. How far from the vertex \\( C \\) of the plot should the boundary points \\( M \\) and \\...
olympiads
Plot the points \( A(4, 1) \), \( B(3, 5) \), \( C(-1, 4) \), and \( D(0, 0) \) on the coordinate plane. Prove that these points are the vertices of a square.
1. **Plot the points on the coordinate plane** The given points are \( A(4, 1) \), \( B(3, 5) \), \( C(-1, 4) \), and \( D(0, 0) \). 2. **Calculate distances between adjacent points** We use the distance formula to check the distances between these points: \[ d = \sqrt{(x_2 - x_1)^2 + (y_2 - y_1)^2} ...
[ { "content": "Plot the points \\( A(4, 1) \\), \\( B(3, 5) \\), \\( C(-1, 4) \\), and \\( D(0, 0) \\) on the coordinate plane. Prove that these points are the vertices of a square.", "role": "user" }, { "content": "\n1. **Plot the points on the coordinate plane**\n\n The given points are \\( A(4, ...
olympiads
A rectangular plot $ABCD$ is divided into two rectangles as shown in the diagram and is contracted to two households, Jia and Yi. Jia's vegetable greenhouse has the same area as Yi’s chicken farm, while the remaining part of Jia's area is 96 acres more than Yi's. Given that $BF = 3 CF$, what is the total area of the re...
Given: \(BF = 3 CF\) 1. Let the area of the rectangle given to 乙 be \( X \) 亩, and the area of the rectangle given to 甲 be \( 3X \) 亩. 2. It is also given that the vegetable garden of 甲 and the chicken farm of 乙 have equal areas. 3. Let the area of the vegetable garden of 甲 and the chicken farm of 乙 be \( Y \) ...
[ { "content": "A rectangular plot $ABCD$ is divided into two rectangles as shown in the diagram and is contracted to two households, Jia and Yi. Jia's vegetable greenhouse has the same area as Yi’s chicken farm, while the remaining part of Jia's area is 96 acres more than Yi's. Given that $BF = 3 CF$, what is th...
olympiads
A surveyor's problem. Using only the length of one side, which is 70 meters, determine the area of a given plot as shown in the map. How can this be done?
1. **Understanding the Problem:** We are given a map of a polygonal field with an unknown area. The map is scaled at $1:10000$. We are also given the length of one side of the field, specifically \(70 \, \text{m}\), which corresponds to \(7 \, \text{cm}\) on the map. 2. **Analysis of the Field’s Shape:** The ...
[ { "content": "A surveyor's problem. Using only the length of one side, which is 70 meters, determine the area of a given plot as shown in the map. How can this be done?", "role": "user" }, { "content": "\n1. **Understanding the Problem:** \n We are given a map of a polygonal field with an unknown...
olympiads
On a plot of land, there are 36 marked circles. Each circle contains a bag with a certain amount of money in dollars, as indicated on the attached diagram. You are allowed to take any number of bags, as long as you do not pass twice along the same straight line. What is the maximum amount of money you can collect?
To determine the maximum sum of dollars that can be collected from the given circular arrangement of bags without revisiting any straight line, we follow these steps: 1. **Understand the Problem:** - We are given 36 circles arranged in the grid as shown in the figure. - Each circle contains a bag of money wi...
[ { "content": "On a plot of land, there are 36 marked circles. Each circle contains a bag with a certain amount of money in dollars, as indicated on the attached diagram. You are allowed to take any number of bags, as long as you do not pass twice along the same straight line. \n\nWhat is the maximum amount of m...
olympiads
Two painters are painting a fence that surrounds garden plots. They come every other day and paint one plot (there are 100 plots) in either red or green. The first painter is colorblind and mixes up the colors; he remembers which plots he painted, but cannot distinguish the color painted by the second painter. The firs...
To determine the maximum number of green-red transitions, we will break the problem down into several logically structured steps: 1. **Partition the Fence Sections into Pairs:** Since there are 100 sections, number them as \( 1, 2, 3, \ldots, 100 \). Group these sections into pairs: \[ (1, 2), (3, 4), \l...
[ { "content": "Two painters are painting a fence that surrounds garden plots. They come every other day and paint one plot (there are 100 plots) in either red or green. The first painter is colorblind and mixes up the colors; he remembers which plots he painted, but cannot distinguish the color painted by the se...
olympiads
Given a geometric sequence \(\{a_{n}\}\) where each term is positive, the first term is 1 and the common ratio is \(x\). The sum of the first \(n\) terms is \(S_{n}\). Define \(f(x) = \lim _{n \rightarrow \infty} \frac{2 S_{n}}{S_{n+1}}\). 1. Find the analytical expression of \(f(x)\). 2. Plot the graph of the functio...
#### (1) 求 $f(x)$ 的解析式; To find the analytic expression for $f(x)$, we need to consider different cases for the common ratio \( x \). ##### Case 1: When \( x = 1 \) 1. If \( x = 1 \), the sequence \( \{a_n\} \) becomes a constant sequence with all terms equal to 1. Hence, the sum of the first \( n \) terms \( S_n \) ...
[ { "content": "Given a geometric sequence \\(\\{a_{n}\\}\\) where each term is positive, the first term is 1 and the common ratio is \\(x\\). The sum of the first \\(n\\) terms is \\(S_{n}\\). Define \\(f(x) = \\lim _{n \\rightarrow \\infty} \\frac{2 S_{n}}{S_{n+1}}\\).\n\n1. Find the analytical expression of \\...
olympiads
Two neighbors ordered sectional fences for their plots. Ivan Ivanovich bought a traditional fence where each section is a rectangle with sides 5 by 2. Petr Petrovich purchased a fence with slanted sections in the form of parallelograms with sides 5 by 2. The number of sections ordered by the neighbors was the same. Com...
1. First, let's analyze the problem and extract the important details: - Ivan Ivanovich bought a traditional fence, each section of which is a rectangle with dimensions $5 \text{ m} \times 2 \text{ m}$. - Petr Petrovich bought a fence with slanted sections in the form of parallelograms with sides $5 \text{ m}$ ...
[ { "content": "Two neighbors ordered sectional fences for their plots. Ivan Ivanovich bought a traditional fence where each section is a rectangle with sides 5 by 2. Petr Petrovich purchased a fence with slanted sections in the form of parallelograms with sides 5 by 2. The number of sections ordered by the neigh...
olympiads
A hypocycloid is the path traced out by a point on the circumference of a circle rolling around the inside circumference of a larger fixed circle. Show that the plots in the (x, y) plane of the solutions \( (x(t), y(t)) \) of the differential equations \( x'' + y' + 6x = 0 \), \( y'' - x' + 6y = 0 \) with initial condi...
To demonstrate that the plots of the solutions \((x(t), y(t))\) of the differential equations \[ x'' + y' + 6x = 0, \] \[ y'' - x' + 6y = 0 \] with initial conditions \( x'(0) = y'(0) = 0 \) are hypocycloids, and to find the possible radii of the circles, we proceed as follows: 1. **Recalling the Dynamics of a Hypocy...
[ { "content": "A hypocycloid is the path traced out by a point on the circumference of a circle rolling around the inside circumference of a larger fixed circle. Show that the plots in the (x, y) plane of the solutions \\( (x(t), y(t)) \\) of the differential equations \\( x'' + y' + 6x = 0 \\), \\( y'' - x' + 6...
olympiads
Investigate the continuity and plot the function $$ f(x)=\left\{\begin{array}{l} x+1.5 \quad \text{for} \quad x<-2 \\ \frac{1}{x} \quad \text{for} \quad -2 \leq x<0 \\ 2x \quad \text{for} \quad x \ge 0 \end{array}\right. $$
1. **Function Definition and Initial Interval Analysis:** The function \( f(x) \) is defined on the entire set of real numbers \(\mathbb{R}\), and it is given by three different expressions corresponding to three intervals of the domain: \[ f(x) = \begin{cases} x + 1.5 & \text{if } x < -2 \\ \fr...
[ { "content": "Investigate the continuity and plot the function\n\n$$\nf(x)=\\left\\{\\begin{array}{l}\nx+1.5 \\quad \\text{for} \\quad x<-2 \\\\\n\\frac{1}{x} \\quad \\text{for} \\quad -2 \\leq x<0 \\\\\n2x \\quad \\text{for} \\quad x \\ge 0\n\\end{array}\\right.\n$$", "role": "user" }, { "content":...
olympiads
Plot the points \((x, y)\) in the plane that satisfy \[ 3^{\left(\frac{1}{x+\left(1 / x\right)}\right)} > 3^{\left(\frac{1}{y+\left(1 / y\right)}\right)} \]
1. **Initial Inequality**: Given the inequality: \[ 3^{\left(\frac{1}{x+\frac{1}{x}}\right)} > 3^{\left(\frac{1}{y+\frac{1}{y}}\right)} \] Since the exponential function $3^z$ is strictly monotonically increasing for all real numbers $z$, the inequality can be simplified by comparing the exponents direc...
[ { "content": "Plot the points \\((x, y)\\) in the plane that satisfy\n\n\\[ 3^{\\left(\\frac{1}{x+\\left(1 / x\\right)}\\right)} > 3^{\\left(\\frac{1}{y+\\left(1 / y\\right)}\\right)} \\]", "role": "user" }, { "content": "\n1. **Initial Inequality**:\n Given the inequality:\n \\[\n 3^{\\left(\...
olympiads
A tractor driver plowed three plots of land. The area of the first plot is \( \frac{2}{5} \) of the area of all three plots combined, and the area of the second plot relates to the area of the third plot as \( \frac{3}{2} \) to \( \frac{4}{3} \). How many hectares were there in all three plots if the third plot was 16 ...
**Step 1:** Define the areas of the three sections. Let the areas of the three sections be \( x \) hectares, \( y \) hectares, and \( x - 16 \) hectares, respectively. According to the problem, the total area is given by the sum of these three sections, which we will call \( A \). **Step 2:** Setup the equations base...
[ { "content": "A tractor driver plowed three plots of land. The area of the first plot is \\( \\frac{2}{5} \\) of the area of all three plots combined, and the area of the second plot relates to the area of the third plot as \\( \\frac{3}{2} \\) to \\( \\frac{4}{3} \\). How many hectares were there in all three ...
olympiads
Calculate the cadastral value of a land plot with an area of 12 acres if the amount of tax paid was 4500 rubles (tax rate $0.3\%$).
To find the cadastral value of the land plot, we need to use the information about the tax paid and the tax rate. 1. Denote the cadastral value of the land by \( V \). 2. Given: - Tax amount paid: \( 4500 \) rubles - Tax rate: \( 0.3\% = 0.003 \) (in decimal form) 3. The tax amount can be calculated using the ...
[ { "content": "Calculate the cadastral value of a land plot with an area of 12 acres if the amount of tax paid was 4500 rubles (tax rate $0.3\\%$).", "role": "user" }, { "content": "\nTo find the cadastral value of the land plot, we need to use the information about the tax paid and the tax rate.\n\n...
olympiads
In the coordinate plane, consider a figure \( M \) consisting of all points with coordinates \( (x, y) \) that satisfy the following system of inequalities: $$ \left\{\begin{array}{l} x + y + |x - y| \leq 0 \\ \frac{x^{2} + 6x + y^{2} - 8y}{x + 3y + 6} \geq 0 \end{array}\right. $$ Plot the figure \( M \) and find its...
1. **Rewriting the first inequality**: The first inequality is given by: \[ x + y + |x - y| \leqslant 0 \] This splits into two cases based on the absolute value function \( |x-y| \): - Case 1: \( x \geq y \) In this case, \( |x - y| = x - y \). Substituting into the inequality: ...
[ { "content": "In the coordinate plane, consider a figure \\( M \\) consisting of all points with coordinates \\( (x, y) \\) that satisfy the following system of inequalities:\n\n$$\n\\left\\{\\begin{array}{l}\nx + y + |x - y| \\leq 0 \\\\\n\\frac{x^{2} + 6x + y^{2} - 8y}{x + 3y + 6} \\geq 0\n\\end{array}\\right...
olympiads
A farmer had a plot of land. He used one third of his land to grow pumpkins, one fourth to grow peas, one fifth to plant beans, and the remaining twenty-six acres were used for corn. How many acres of land did the farmer have?
1. Let's denote the total area of the land by \( A \) acres. 2. The area is divided into four parts: - One-third for growing pumpkins. - One-fourth for growing peas. - One-fifth for planting beans. - The rest, which is given as 26 acres, is for corn. 3. First, we convert all fractions to a common denomin...
[ { "content": "A farmer had a plot of land. He used one third of his land to grow pumpkins, one fourth to grow peas, one fifth to plant beans, and the remaining twenty-six acres were used for corn.\n\nHow many acres of land did the farmer have?", "role": "user" }, { "content": "\n1. Let's denote the ...
olympiads
In the 6 plots of land as shown in the figure, plant either type A or type B vegetables (it is possible to plant only one type, or both types), with the requirement that adjacent plots should not both have type A vegetables. How many different planting schemes are there? $\qquad$
We want to plant two types of vegetables, labeled \(A\) and \(B\), on 6 plots of land with the constraint that no two adjacent plots can both have vegetable \(A\). First, let's consider the possible cases for \( n \), the number of plots planted with vegetable \(A\): 1. \( n = 0 \): None of the plots have vegetable ...
[ { "content": "In the 6 plots of land as shown in the figure, plant either type A or type B vegetables (it is possible to plant only one type, or both types), with the requirement that adjacent plots should not both have type A vegetables. How many different planting schemes are there? $\\qquad$", "role": "u...
olympiads
A plot of land in the shape of a trapezoid has parallel sides of 2100 meters and 1500 meters, and the lengths of the other two sides are 613 meters and 37 meters. How many square fathoms is the area of the land?
We are given a trapezoidal plot with the following dimensions: - Parallel sides: \( AB = 2100 \) meters and \( CD = 1500 \) meters - Non-parallel sides: \( DA = 37 \) meters and \( BC = 613 \) meters To find the area of the trapezoid in "négyszögöl," we first need to determine its area in square meters. 1. **Finding...
[ { "content": "A plot of land in the shape of a trapezoid has parallel sides of 2100 meters and 1500 meters, and the lengths of the other two sides are 613 meters and 37 meters. How many square fathoms is the area of the land?", "role": "user" }, { "content": "\nWe are given a trapezoidal plot with t...
olympiads
Construct a circle of radius 1 with its center at the origin. Through an arbitrary point on the x-axis \((x ; 0)\), draw a line parallel to the y-axis. Let \(y\) denote the number of intersection points between this line and the circle. Plot the graph representing the relationship between \(x\) and \(y\), and express t...
1. **Construct the Circle:** - We need to construct a circle with radius \( r = 1 \) and center at the origin \((0, 0)\). - The equation of this circle is given by: \[ x^2 + y^2 = 1 \] 2. **Draw a Vertical Line Through an Arbitrary Point on the x-axis:** - Let's take an arbitrary point on the ...
[ { "content": "Construct a circle of radius 1 with its center at the origin. Through an arbitrary point on the x-axis \\((x ; 0)\\), draw a line parallel to the y-axis. Let \\(y\\) denote the number of intersection points between this line and the circle. Plot the graph representing the relationship between \\(x...
olympiads
Plot the points in the Cartesian coordinate system that satisfy the conditions: $$ -2 \leq x \leq 2, \quad -3 \leq y \leq 3, \quad \{x\} \leq \{y\} $$ (Where $\{z\}$ denotes the fractional part of the number $z$.)
1. **Define the Region:** We start by defining the region given by the inequalities: \[ -2 \leq x \leq 2 \quad \text{and} \quad -3 \leq y \leq 3 \] 2. **Partition into Unit Squares:** We partition this region into unit squares by drawing lines parallel to the axes through integer coordinate points. T...
[ { "content": "Plot the points in the Cartesian coordinate system that satisfy the conditions:\n\n$$\n-2 \\leq x \\leq 2, \\quad -3 \\leq y \\leq 3, \\quad \\{x\\} \\leq \\{y\\}\n$$\n\n(Where $\\{z\\}$ denotes the fractional part of the number $z$.)", "role": "user" }, { "content": "\n1. **Define the...
olympiads
Consider the data points \(a_1, a_2, a_3, \ldots, a_n\). The arithmetic mean of these data points is determined using the following graphical method. The data points are plotted on a Cartesian coordinate system with points on the line \(x = 0, 2, 4, \ldots, 2(n-1)\) corresponding to points \(A_0, A_2, A_4, \ldots, A_{...
The aim is to show that the graphical method described indeed provides the arithmetic mean of the given data points $a_1, a_2, a_3, \ldots, a_n$. This will be done by mathematical induction. **Base Case**: For $n=2$, calculate the midpoint ordinates and verify that they give the arithmetic mean. In this case, there ...
[ { "content": "\nConsider the data points \\(a_1, a_2, a_3, \\ldots, a_n\\). The arithmetic mean of these data points is determined using the following graphical method. The data points are plotted on a Cartesian coordinate system with points on the line \\(x = 0, 2, 4, \\ldots, 2(n-1)\\) corresponding to points...
olympiads
A tractor brigade can plow 5/6 of a plot of land in 4 hours and 15 minutes. Before the lunch break, the brigade worked for 4.5 hours, after which 8 hectares remained unplowed. How large was the plot of land?
1. **Understand the Given Information:** - The team can plow \( \frac{5}{6} \) of a field in 4 hours and 15 minutes. - Before the lunch break, the team worked for 4.5 hours. - After the break, 8 hectares of the field remained unplowed. - We need to find the total area \( x \) of the field. 2. **Convert Ti...
[ { "content": "A tractor brigade can plow 5/6 of a plot of land in 4 hours and 15 minutes. Before the lunch break, the brigade worked for 4.5 hours, after which 8 hectares remained unplowed. How large was the plot of land?", "role": "user" }, { "content": "\n1. **Understand the Given Information:**\n...
olympiads
An empty bucket begins to receive water through a tap at a rate of 4 kilograms per minute. The bucket can hold 10 kilograms of water. Plot a graph showing the dependence of the mass of water \(m\) (kg) in the bucket on time \(t\) (minutes) if the observation lasts for 5 minutes. Write the dependency between \(m\) and \...
1. **Understanding the problem:** - Water flows into an empty bucket through a tap at a rate of 4 kilograms per minute. - The bucket has a maximum capacity of 10 kilograms of water. - The observation period lasts for 5 minutes. 2. **Determine the relationship between the mass of water \(m\) in the bucket and...
[ { "content": "An empty bucket begins to receive water through a tap at a rate of 4 kilograms per minute. The bucket can hold 10 kilograms of water. Plot a graph showing the dependence of the mass of water \\(m\\) (kg) in the bucket on time \\(t\\) (minutes) if the observation lasts for 5 minutes. Write the depe...
olympiads
Ctibor marked a square land plot on a map with a scale of 1:50000 and calculated that its side corresponds to $1 \mathrm{~km}$ in reality. He then resized the map on a copier such that the marked square had an area $1.44 \mathrm{~cm}^{2}$ smaller than the original. What was the scale of the resized map? Hint: What we...
1. **Determine the side length of the marked square on the original map**: The original map has a scale of 1:50000. Given that the actual side length of the square is 1 km, we can calculate the length of the side of the square on the original map by converting 1 km to cm (1 km = 100000 cm), and then using the sca...
[ { "content": "Ctibor marked a square land plot on a map with a scale of 1:50000 and calculated that its side corresponds to $1 \\mathrm{~km}$ in reality. He then resized the map on a copier such that the marked square had an area $1.44 \\mathrm{~cm}^{2}$ smaller than the original.\n\nWhat was the scale of the r...
olympiads
A rectangular field is divided into 100 congruent rectangular plots using lines parallel to its sides, with each plot sharing one side with an adjacent plot. Initially, 9 plots are weedy. A plot becomes weedy if at least two of its neighbors are weedy. Is it possible that eventually the entire field becomes weedy?
We are given a rectangular field divided into $100$ congruent smaller rectangular parcels using lines parallel to the sides of the rectangle. Initially, $9$ parcels are overgrown with weeds. A parcel becomes overgrown if at least two of its neighbors are overgrown. We need to determine if it is possible for the entire ...
[ { "content": "A rectangular field is divided into 100 congruent rectangular plots using lines parallel to its sides, with each plot sharing one side with an adjacent plot. Initially, 9 plots are weedy. A plot becomes weedy if at least two of its neighbors are weedy. Is it possible that eventually the entire fie...
olympiads
A "stem-and-leaf" plot is often used to represent whole numbers or decimal fractions. In this type of diagram, it's convenient to display people's ages. Suppose there are 5 people in a studied group, aged 19, 34, 37, 42, and 48 years. The diagram for this group will look as shown in Figure 2. The left column is the "st...
To solve this problem, we need to determine the number of years that have passed based on the given stem-and-leaf plots and the described transformations in age distribution as a function of time. We also need to reconstruct the diagram with the new age distribution. Let's proceed step-by-step: 1. **Initial Analysis...
[ { "content": "A \"stem-and-leaf\" plot is often used to represent whole numbers or decimal fractions. In this type of diagram, it's convenient to display people's ages. Suppose there are 5 people in a studied group, aged 19, 34, 37, 42, and 48 years. The diagram for this group will look as shown in Figure 2. Th...
olympiads
A square field is divided into 100 equal plots, 9 of which are overgrown with weeds. It is known that weeds spread over the year to those plots that have at least two neighboring plots already infected with weeds (plots are neighbors if they share a side). Prove that the entire field will not become overgrown with weed...
1. **Initial Observations**: - The given square field is divided into \(100\) equal parts. - Out of these, \(9\) parts are infested with weeds initially. - Weed spreads to a part if and only if it has at least two adjacent parts already infested. 2. **Boundary Analysis**: - Let us analyze the boundary o...
[ { "content": "A square field is divided into 100 equal plots, 9 of which are overgrown with weeds. It is known that weeds spread over the year to those plots that have at least two neighboring plots already infected with weeds (plots are neighbors if they share a side). Prove that the entire field will not beco...
olympiads
The areas of three plots of land are in the ratio \(2 \frac{3}{4}: 1 \frac{5}{6}: 1 \frac{3}{8}\). It is known that 72 quintals more grain were collected from the first plot than from the second. Find the area of all three plots if the average yield is 18 quintals per hectare.
We are given the areas of three land plots in the ratios \(2 \frac{3}{4} : 1 \frac{5}{6} : 1 \frac{3}{8}\). Additionally, it's given that the amount of grain harvested from the first plot is 72 quintals more than from the second plot. The average yield is 18 quintals per hectare. We need to find the total area of all t...
[ { "content": "The areas of three plots of land are in the ratio \\(2 \\frac{3}{4}: 1 \\frac{5}{6}: 1 \\frac{3}{8}\\). It is known that 72 quintals more grain were collected from the first plot than from the second. Find the area of all three plots if the average yield is 18 quintals per hectare.", "role": "...
olympiads
Two neighbors ordered sectional fences for their plots. Ivan Ivanovich bought a traditional fence where each section is a rectangle with sides 5 by 2. Petr Petrovich purchased a fence with slanted sections in the form of parallelograms with sides 5 by 2. The number of sections ordered by the neighbors was the same. Com...
1. First, let's analyze the problem and extract the important details: - Ivan Ivanovich bought a traditional fence, each section of which is a rectangle with dimensions $5 \text{ m} \times 2 \text{ m}$. - Petr Petrovich bought a fence with slanted sections in the form of parallelograms with sides $5 \text{ m}$ ...
[ { "content": "Two neighbors ordered sectional fences for their plots. Ivan Ivanovich bought a traditional fence where each section is a rectangle with sides 5 by 2. Petr Petrovich purchased a fence with slanted sections in the form of parallelograms with sides 5 by 2. The number of sections ordered by the neigh...
olympiads
In the center of a square plot, there is a wolf, and at each of the 4 vertices of the square, there is a dog. The wolf can run freely within the entire plot, while the dogs can only run along the boundaries of the square. It is known that the wolf can kill a single dog, but two dogs together can kill the wolf. Each dog...
1. **Define Variables:** Let \( v \) be the maximum speed of the wolf. 2. **Consider the Geometry:** In the square plot with one wolf at the center and a dog at each corner. Construct parallel lines to the diagonals of the square through the center where the wolf is located. These lines intersect the boundary o...
[ { "content": "In the center of a square plot, there is a wolf, and at each of the 4 vertices of the square, there is a dog. The wolf can run freely within the entire plot, while the dogs can only run along the boundaries of the square. It is known that the wolf can kill a single dog, but two dogs together can k...
olympiads
Plot the solution set of the system of equations \(\left\{\begin{array}{l} x - 2y = 1 \\ x^{3} - 6xy - 8y^{3} = 1 \end{array}\right.\) on the coordinate plane.
1. **Given system of equations**: \[ \begin{cases} x - 2y = 1 \\ x^3 - 6xy - 8y^3 = 1 \end{cases} \] 2. **Rewriting the first equation**: Given: \[ x - 2y = 1 \] We can express \(x\) in terms of \(y\): \[ x = 2y + 1 \] 3. **Substituting \(x = 2y + 1\) into the second equati...
[ { "content": "Plot the solution set of the system of equations \\(\\left\\{\\begin{array}{l} x - 2y = 1 \\\\ x^{3} - 6xy - 8y^{3} = 1 \\end{array}\\right.\\) on the coordinate plane.", "role": "user" }, { "content": "\n1. **Given system of equations**:\n \\[\n \\begin{cases}\n x - 2y = 1 \\\\\...
olympiads
A small garden of size $6 \times 7$ meters is divided into 5 square plots. All boundaries between the plots are parallel to the sides of the square, and the side of each plot is an integer number of meters. Find the total length of the resulting boundaries, considering the boundaries as lines with no thickness. Answer...
1. **Determine the Area Division**: Given the garden has dimensions $6 \times 7$ meters, the total area is: \[ \text{Total area} = 6 \times 7 = 42 \text{ square meters} \] We need to divide this area into 5 squares with integer side lengths. 2. **Possible Division**: The only possible way to divide ...
[ { "content": "A small garden of size $6 \\times 7$ meters is divided into 5 square plots. All boundaries between the plots are parallel to the sides of the square, and the side of each plot is an integer number of meters. Find the total length of the resulting boundaries, considering the boundaries as lines wit...
olympiads
Plot in the Cartesian coordinate system the pairs of real numbers $(x, y)$ for which $$ \frac{x}{y}+\frac{1}{x}+y \geq \frac{y}{x}+\frac{1}{y}+x $$
Given the inequality: \[ \frac{x}{y} + \frac{1}{x} + y \geq \frac{y}{x} + \frac{1}{y} + x \] we need to find the region in the $xy$-plane that satisfies this inequality. 1. **Transform the Inequality:** - Begin by rearranging the terms of the inequality. \[ \frac{x}{y} - \frac{y}{x} + \frac{1}{x} - \fr...
[ { "content": "Plot in the Cartesian coordinate system the pairs of real numbers $(x, y)$ for which\n\n$$\n\\frac{x}{y}+\\frac{1}{x}+y \\geq \\frac{y}{x}+\\frac{1}{y}+x\n$$", "role": "user" }, { "content": "\nGiven the inequality:\n\n\\[\n\\frac{x}{y} + \\frac{1}{x} + y \\geq \\frac{y}{x} + \\frac{1}...
olympiads
Plot the set of points on the coordinate plane whose coordinates satisfy the equation \((x^{2}+3xy+2y^{2})(x^{2}y^{2}-1)=0\).
To solve the given equation: \[ \left(x^{2}+3xy+2y^{2}\right)\left(x^{2}y^{2}-1\right)=0 \] 1. **Factor the first parenthesis**: \[ x^{2} + 3xy + 2y^{2} = (x + 2y)(x + y) \] This comes from recognizing that \(x^{2} + 3xy + 2y^{2}\) is a quadratic trinomial that can be factored into the product of two binom...
[ { "content": "Plot the set of points on the coordinate plane whose coordinates satisfy the equation \\((x^{2}+3xy+2y^{2})(x^{2}y^{2}-1)=0\\).", "role": "user" }, { "content": "To solve the given equation:\n\\[\n\\left(x^{2}+3xy+2y^{2}\\right)\\left(x^{2}y^{2}-1\\right)=0\n\\]\n\n1. **Factor the firs...
olympiads
1. Construct stencils from dense paper for plotting the graphs of the following functions: \( y = x^{2}, y = x^{3} \), and \( y = |x| \). Using these stencils, plot the graphs of these three functions on three separate sheets of paper. 2. On the first sheet, plot the function \( y = x^{2} - 2 \). On the second sheet,...
1. **Step 1: Constructing Graphs for \( y = x^2 - 2 \), \( y = x^3 - 2 \), and \( y = |x| - 2 \) Using Stencils** To construct the graphs of \( y = x^2 - 2 \), \( y = x^3 - 2 \), and \( y = |x| - 2 \), we can use the stencils of the basic functions \( y = x^2 \), \( y = x^3 \), and \( y = |x| \). - **Graph of \...
[ { "content": "\n1. Construct stencils from dense paper for plotting the graphs of the following functions: \\( y = x^{2}, y = x^{3} \\), and \\( y = |x| \\). Using these stencils, plot the graphs of these three functions on three separate sheets of paper.\n\n2. On the first sheet, plot the function \\( y = x^{2...
olympiads
The image shows the boundaries of four equally-sized rectangular plots indicated by a dotted line. The built-up area is highlighted in gray, forming a rectangle with one side coinciding with the boundary of the plots. The numbers shown represent the area of the undeveloped land on each individual plot, expressed in $\m...
1. **Identify the Problem:** - We need to calculate the total area of the built-up space. - The diagram provided has four equally sized rectangular plots, marked with the areas of the non-built-up (free) space in each plot. 2. **Break Down the Free Spaces:** - Given the areas of free spaces as \(480\, \mathrm...
[ { "content": "The image shows the boundaries of four equally-sized rectangular plots indicated by a dotted line. The built-up area is highlighted in gray, forming a rectangle with one side coinciding with the boundary of the plots. The numbers shown represent the area of the undeveloped land on each individual ...
olympiads
It is known that the number of birch trees in a certain mixed forest plot ranges from $13\%$ to $14\%$ of the total number of trees. Find the minimum possible total number of trees in this plot.
Let's denote the total number of trees in the mixed forest as \( L \) and the number of birches as \( X \). We are given that the percentage of birches in the forest ranges from \( 13\% \) to \( 14\% \) of the total number of trees. Therefore, we can express this as a mathematical inequality: \[ 0.13 < \frac{X}{L} < ...
[ { "content": "It is known that the number of birch trees in a certain mixed forest plot ranges from $13\\%$ to $14\\%$ of the total number of trees. Find the minimum possible total number of trees in this plot.", "role": "user" }, { "content": "\nLet's denote the total number of trees in the mixed f...
olympiads
A team of lumberjacks was cutting trees in large and small plots, where the area of the small plot is 3 times less than the area of the large plot. The part of the team working on the large plot had 8 more lumberjacks than the part working on the small plot. When the tree cutting on the large plot was finished, the par...
We are given that a team of lumberjacks is working on both a large and a small plot of land. The area of the small plot is three times less than that of the large plot. Additionally, there are 8 more lumberjacks working on the large plot than on the small plot. We aim to determine the maximum number of lumberjacks that...
[ { "content": "A team of lumberjacks was cutting trees in large and small plots, where the area of the small plot is 3 times less than the area of the large plot. The part of the team working on the large plot had 8 more lumberjacks than the part working on the small plot. When the tree cutting on the large plot...
olympiads
For each of the following functions, find the points of discontinuity if they exist, determine the jump of the function at each point of discontinuity, and plot the graph: 1) \( f(x)=\left\{\begin{array}{c}-\frac{1}{2} x^{2} \text{ for } x \leq 2 \\ x \text{ for } x > 2 \end{array}\right. \) 2) \( \varphi(x)= \begin{ca...
Let's investigate the points of discontinuity for each given function and calculate the jumps at these points. #### 1. \( f(x) = \begin{cases} -\frac{1}{2} x^2 & \text{ if } x \leq 2, \\ x & \text{ if } x > 2 \end{cases} \) 1. Analyze \( f(x) \) at \( x = 2 \): - Calculate the left-hand limit: \[ \li...
[ { "content": "For each of the following functions, find the points of discontinuity if they exist, determine the jump of the function at each point of discontinuity, and plot the graph:\n1) \\( f(x)=\\left\\{\\begin{array}{c}-\\frac{1}{2} x^{2} \\text{ for } x \\leq 2 \\\\ x \\text{ for } x > 2 \\end{array}\\ri...
olympiads
At 2 p.m., Sanjay measures the temperature to be 3°C. He measures the temperature every hour after this until 10 p.m. He plots the temperatures that he measures on the graph shown. At what time after 2 p.m. does he again measure a temperature of 3°C? (A) 9 p.m. (B) 5 p.m. (C) 8 p.m. (D) 10 p.m. (E) 7 p.m.
1. **Determine the reference line for $3^\circ \mathrm{C}$**: - Since $3^\circ \mathrm{C}$ is halfway between $2^\circ \mathrm{C}$ and $4^\circ \mathrm{C}$, we can identify the horizontal line that represents $3^\circ \mathrm{C}$ on the vertical axis of the graph. This line will be used to check the corresponding ...
[ { "content": "At 2 p.m., Sanjay measures the temperature to be 3°C. He measures the temperature every hour after this until 10 p.m. He plots the temperatures that he measures on the graph shown. At what time after 2 p.m. does he again measure a temperature of 3°C?\n(A) 9 p.m.\n(B) 5 p.m.\n(C) 8 p.m.\n(D) 10 p.m...
olympiads
On a square plot with a side length of 100, cylindrical trees with a radius of 1 are growing. Prove that if it is impossible to lay a straight path of length 10 on this plot, no matter how thin, without touching any tree, then the number of trees on the plot is at least 400.
1. We are given a square plot with side length 100 units, covered with cylindrical trees of radius 1 unit. 2. We need to prove that if no straight path of length 10 units can be laid without touching a tree, then the number of trees on the plot is at least 400. #### Step-by-step solution: 1. **Partition the Plot:** ...
[ { "content": "On a square plot with a side length of 100, cylindrical trees with a radius of 1 are growing. Prove that if it is impossible to lay a straight path of length 10 on this plot, no matter how thin, without touching any tree, then the number of trees on the plot is at least 400.", "role": "user" ...
olympiads
Let \( m \) and \( n \) be two relatively prime positive integers. Prove that if the fractions: \[ \begin{aligned} & \frac{m+n}{m}, \frac{2(m+n)}{m}, \frac{3(m+n)}{m}, \ldots, \frac{(m-1)(m+n)}{m}, \\ & \frac{m+n}{n}, \frac{2(m+n)}{n}, \frac{3(m+n)}{n}, \ldots, \frac{(n-1)(m+n)}{n} \end{aligned} \] are plotted as poi...
1. Initially, note that for the considered fractions, none can be an integer. Specifically, if a fraction $\frac{k(m+n)}{m}$ (where $k$ is one of the numbers $1, 2, ..., m-1$) were an integer, then $m+n$ would need to have common divisors with $m$. Since $k < m$, $k$ cannot be a multiple of $m$, hence no simplified fr...
[ { "content": "Let \\( m \\) and \\( n \\) be two relatively prime positive integers. Prove that if the fractions:\n\n\\[\n\\begin{aligned}\n& \\frac{m+n}{m}, \\frac{2(m+n)}{m}, \\frac{3(m+n)}{m}, \\ldots, \\frac{(m-1)(m+n)}{m}, \\\\\n& \\frac{m+n}{n}, \\frac{2(m+n)}{n}, \\frac{3(m+n)}{n}, \\ldots, \\frac{(n-1)(...
olympiads
Plot the graph of the function \( y = (4 \sin 4 x - 2 \cos 2 x + 3)^{0.5} + (4 \cos 4 x + 2 \cos 2 x + 3)^{0.5} \).
To find the graph of the function \(y = \left(4 \sin^4 x - 2 \cos 2x + 3\right)^{0.5} + \left(4 \cos^4 x + 2 \cos 2x + 3\right)^{0.5}\), let's go through the steps of simplification in detail. 1. **Rewrite the function using trigonometric identities**: The given function is: \[ y = \sqrt{4 \sin^4 x - 2 \cos ...
[ { "content": "Plot the graph of the function \\( y = (4 \\sin 4 x - 2 \\cos 2 x + 3)^{0.5} + (4 \\cos 4 x + 2 \\cos 2 x + 3)^{0.5} \\).", "role": "user" }, { "content": "\nTo find the graph of the function \\(y = \\left(4 \\sin^4 x - 2 \\cos 2x + 3\\right)^{0.5} + \\left(4 \\cos^4 x + 2 \\cos 2x + 3...
olympiads
Formulate the equation of the locus of points that are equidistant from the point \( F(0, -3) \) and the line \( y + 5 = 0 \). Plot this curve.
1. **Identify the points and the geometric condition:** We are given a point \( F(0, -3) \) and a line \( y + 5 = 0 \), or equivalently, \( y = -5 \). 2. **Formulate the geometric condition mathematically:** We need to find the set of points \( M(x, y) \) such that the distance \( d_1 \) from \( M \) to poi...
[ { "content": "Formulate the equation of the locus of points that are equidistant from the point \\( F(0, -3) \\) and the line \\( y + 5 = 0 \\). \n\nPlot this curve.", "role": "user" }, { "content": "\n1. **Identify the points and the geometric condition:** \n We are given a point \\( F(0, -3) \\...
olympiads
A student plots the graph of the function \( y = ax^2 + bx + c \) (\( a \neq 0 \)) by taking 7 values of the independent variable \( x_1 < x_2 < \cdots < x_7 \) such that \( x_2 - x_1 = x_3 - x_2 = \cdots = x_7 - x_6 \), and calculates the corresponding values of \( y \). The results are listed in the table below. \beg...
1. Let's denote the sequence of $x$ values as $x_1, x_2, \ldots, x_7$. 2. Given that $x_{2} - x_{1} = x_{3} - x_{2} = \cdots = x_{7} - x_{6} = d$, where $d$ is the common difference of the sequence. 3. Let the function be given by $y = ax^2 + bx + c$. 4. Each $y_i$ represents the function evaluated at $x_i$ for $i = 1...
[ { "content": "A student plots the graph of the function \\( y = ax^2 + bx + c \\) (\\( a \\neq 0 \\)) by taking 7 values of the independent variable \\( x_1 < x_2 < \\cdots < x_7 \\) such that \\( x_2 - x_1 = x_3 - x_2 = \\cdots = x_7 - x_6 \\), and calculates the corresponding values of \\( y \\). The results ...
olympiads
Calculate the amount of personal income tax (НДФЛ) paid by Sergey over the past year if he is a resident of the Russian Federation and had a stable income of 30,000 rubles per month and a one-time vacation bonus of 20,000 rubles during this period. Last year, Sergey sold his car, which he inherited two years ago, for 2...
1. Calculate the total income for the year: \[ \text{Monthly income} = 30000 \, \text{rub./month} \] Duration: 12 months. \[ \text{Annual income from salary} = 30000 \times 12 = 360000 \, \text{rub.} \] Add any additional income: \[ \text{Bonus} = 20000 \, \text{rub.} \...
[ { "content": "Calculate the amount of personal income tax (НДФЛ) paid by Sergey over the past year if he is a resident of the Russian Federation and had a stable income of 30,000 rubles per month and a one-time vacation bonus of 20,000 rubles during this period. Last year, Sergey sold his car, which he inherite...
olympiads
In a park, there are \( m n \) paths and several grass plots. Each path connects two grass plots. It is known that each path can be painted with one of \( m \) colors such that no two paths emerging from the same grass plot have the same color. Prove that there exists a way to paint the paths such that there are exactl...
To solve this problem, we need to demonstrate that there exists a way to color each of the \(mn\) paths with one of \(m\) colors such that each patch of grass has exactly \(n\) paths of each color connected to it. 1. **Define the Problem Statement Precisely:** - We are given \(mn\) paths and a certain number ...
[ { "content": "In a park, there are \\( m n \\) paths and several grass plots. Each path connects two grass plots. It is known that each path can be painted with one of \\( m \\) colors such that no two paths emerging from the same grass plot have the same color. Prove that there exists a way to paint the paths ...
olympiads
Find the approximate values of the roots of the function \( y = 0.3x^3 - 2x^2 - 0.2x + 0.5 \) by plotting its graph on the interval \([-1, 3]\).
To find the approximate values of the roots of the function \( y = 0.3x^3 - 2x^2 - 0.2x + 0.5 \), we need to determine the values of \( x \) where the function evaluates to zero, i.e., \( y = 0 \). 1. **Express the function**: \[ y = 0.3x^3 - 2x^2 - 0.2x + 0.5 \] 2. **Set the function to zero**: \[ 0.3...
[ { "content": "Find the approximate values of the roots of the function \\( y = 0.3x^3 - 2x^2 - 0.2x + 0.5 \\) by plotting its graph on the interval \\([-1, 3]\\).", "role": "user" }, { "content": "To find the approximate values of the roots of the function \\( y = 0.3x^3 - 2x^2 - 0.2x + 0.5 \\), we ...
olympiads
A farmer claims that with four rods, he can fence a square plot of land sufficient for one sheep. If this is true, what is the minimum number of rods needed to fence an area for ten sheep? The answer depends on the shape of your fence. How many rods are required for 10 sheep?
: 1. **Understanding the Efficiency of Shapes:** - A farmer claims that with four poles, he can enclose a square area just sufficient for one sheep. - We need to determine the minimum number of poles required to enclose an area sufficient for ten sheep. 2. **Optimal Shape Analysis:** - From geometry, the o...
[ { "content": "A farmer claims that with four rods, he can fence a square plot of land sufficient for one sheep. If this is true, what is the minimum number of rods needed to fence an area for ten sheep? The answer depends on the shape of your fence. \n\nHow many rods are required for 10 sheep?", "role": "us...
olympiads
Find the coordinates of the center of curvature and plot the curve and the circle of curvature for the curve: 1) \( y = 4x - x^2 \) at its vertex; 2) \( x = t - \sin t, \, y = 1 - \cos t \) at the point where \( t = \frac{\pi}{2} \).
1. **Problem Statement**: - We are given two problems to solve. First, we need to find the coordinates of the center of curvature and draw the curvature circle for the parabola \(y = 4x - x^2\) at its vertex. Second, we need to do the same for the parametric curve \(x = t - \sin t\) and \(y = 1 - \cos t\) at the po...
[ { "content": "Find the coordinates of the center of curvature and plot the curve and the circle of curvature for the curve:\n1) \\( y = 4x - x^2 \\) at its vertex;\n2) \\( x = t - \\sin t, \\, y = 1 - \\cos t \\) at the point where \\( t = \\frac{\\pi}{2} \\).", "role": "user" }, { "content": "\n1. ...
olympiads
When land plots were being allocated, farmer Novoselov was assigned 2 square plots of different areas with integer side lengths. Is it possible to assign farmer Malinnikov 2 square plots with integer side lengths such that the total area of Malinnikov's plots is 2 times greater than the total area of Novoselov's plots?
1. Denote the sides of the squares allocated to farmer Novoselov as \( x \) and \( y \) such that \( x > y \). - Hence, the areas of these squares are \( x^2 \) and \( y^2 \). 2. The total area of the squares allocated to Novoselov is: \[ a = x^2 + y^2 \] 3. According to the problem, the total area of th...
[ { "content": "When land plots were being allocated, farmer Novoselov was assigned 2 square plots of different areas with integer side lengths. Is it possible to assign farmer Malinnikov 2 square plots with integer side lengths such that the total area of Malinnikov's plots is 2 times greater than the total area...
olympiads
The length of a rectangular plot is 4 meters, and the width is 1 meter. Is it possible to plant three trees on it so that the distance between any two trees is at least 2.5 meters?
: 1. Let's denote the rectangular plot as \(ABCD\), with dimensions 4 meters by 1 meter. 2. We are asked if we can place three trees on this plot such that the distance between any two of them is at least 2.5 meters. 3. To analyze this, we will divide this rectangle into two smaller rectangles, each of dimensions \(2...
[ { "content": "The length of a rectangular plot is 4 meters, and the width is 1 meter.\n\nIs it possible to plant three trees on it so that the distance between any two trees is at least 2.5 meters?", "role": "user" }, { "content": ": \n\n1. Let's denote the rectangular plot as \\(ABCD\\), with dimen...
olympiads
When harvesting, 210 quintals of wheat were collected from each of two plots. The area of the first plot is 0.5 hectares less than the area of the second plot. How many quintals of wheat were collected per hectare on each plot, given that the wheat yield per hectare on the first plot was 1 quintal higher than on the se...
1. Let \( x \) hectares be the area of the first plot. Therefore, the area of the second plot is \( x + 0.5 \) hectares. 2. The yield from the first plot per hectare is \(\frac{210}{x}\) quintals, and from the second plot it is \(\frac{210}{x+0.5}\) quintals. 3. According to the condition, the yield from the first p...
[ { "content": "When harvesting, 210 quintals of wheat were collected from each of two plots. The area of the first plot is 0.5 hectares less than the area of the second plot. How many quintals of wheat were collected per hectare on each plot, given that the wheat yield per hectare on the first plot was 1 quintal...
olympiads
Calculate the cadastral value of a land plot with an area of 12 acres if the amount of tax paid was 4500 rubles (tax rate $0.3\%$).
To find the cadastral value of the land plot, we need to use the information about the tax paid and the tax rate. 1. Denote the cadastral value of the land by \( V \). 2. Given: - Tax amount paid: \( 4500 \) rubles - Tax rate: \( 0.3\% = 0.003 \) (in decimal form) 3. The tax amount can be calculated using the ...
[ { "content": "Calculate the cadastral value of a land plot with an area of 12 acres if the amount of tax paid was 4500 rubles (tax rate $0.3\\%$).", "role": "user" }, { "content": "\nTo find the cadastral value of the land plot, we need to use the information about the tax paid and the tax rate.\n\n...
olympiads
On fields allocated to an agricultural laboratory for experiments, 14.7 centners of grain were harvested from two plots. The following year, after applying new agricultural techniques, the yield on the first plot increased by 80%, and on the second plot by 24%, resulting in a total harvest of 21.42 centners from the sa...
1. Let's denote: - $x$ as the amount of grain collected from the first field after applying new agrotechnic methods. - $y$ as the amount of grain collected from the second field after applying new agrotechnic methods. 2. According to the problem, we have the following conditions: \[ x + y = 21.42 \quad \t...
[ { "content": "On fields allocated to an agricultural laboratory for experiments, 14.7 centners of grain were harvested from two plots. The following year, after applying new agricultural techniques, the yield on the first plot increased by 80%, and on the second plot by 24%, resulting in a total harvest of 21.4...
olympiads
A square plot was expanded so that the new square has a side that is 5 meters longer than the side of the original square, and its area increased by 225 square meters. What is the area of the original plot?
1. Let \( s \) be the side length of the original square. 2. The side length of the new square is \( s + 5 \) meters. 3. The area of the original square is \( s^2 \). 4. The area of the new square is \( (s + 5)^2 \). 5. The problem states that the area has increased by 225 m\(^2\). Thus, we set up the equation: \[ ...
[ { "content": "A square plot was expanded so that the new square has a side that is 5 meters longer than the side of the original square, and its area increased by 225 square meters. What is the area of the original plot?", "role": "user" }, { "content": "1. Let \\( s \\) be the side length of the or...
olympiads
Given the motion equation of a point $\bar{r}=\cos ^{3} t \cdot \bar{i}+\sin ^{3} t \cdot \bar{j}$, plot its trajectory and the vectors of velocity and acceleration at the moments in time $t_{1}=\frac{\pi}{6}$ and $t_{2}=\frac{\pi}{4}$.
1. **Trajectories and Conversions:** The given position vector of the point is: \[ \bar{r}(t) = \cos^3(t) \cdot \bar{i} + \sin^3(t) \cdot \bar{j} \] To find the trajectory of this point, we note that \(x = \cos^3(t)\) and \(y = \sin^3(t)\). This represents the parametric equations of an astroid. 2. **Ve...
[ { "content": "\nGiven the motion equation of a point $\\bar{r}=\\cos ^{3} t \\cdot \\bar{i}+\\sin ^{3} t \\cdot \\bar{j}$, plot its trajectory and the vectors of velocity and acceleration at the moments in time $t_{1}=\\frac{\\pi}{6}$ and $t_{2}=\\frac{\\pi}{4}$.", "role": "user" }, { "content": "1....
olympiads
For a random variable \( X \) defined by the distribution function \( F(x) \) as follows: - \( F(x) = 0 \) for \( x < 2 \), - \( F(x) = a(x-2)^2 \) for \( 2 \leq x \leq 4 \), - \( F(x) = 1 \) for \( x > 4 \), Determine: 1. The value of the parameter \( a \). 2. The probability density function \( f(x) \). 3. The first...
Given the distribution function for a random variable \( X \): \[ F(x) = \begin{cases} 0 & \text{for } x < 2, \\ a(x-2)^2 & \text{for } 2 \leq x \leq 4, \\ 1 & \text{for } x > 4, \end{cases} \] we need to find the parameter \( a \), the density function \( f(x) \), the first four moments, the skewness, and kurt...
[ { "content": "For a random variable \\( X \\) defined by the distribution function \\( F(x) \\) as follows:\n- \\( F(x) = 0 \\) for \\( x < 2 \\),\n- \\( F(x) = a(x-2)^2 \\) for \\( 2 \\leq x \\leq 4 \\),\n- \\( F(x) = 1 \\) for \\( x > 4 \\),\n\nDetermine:\n1. The value of the parameter \\( a \\).\n2. The prob...
olympiads
Farmers Ivanov, Petrov, Sidorov, Vasilev and Ermolaev own rectangular plots of land, the areas of which are indicated in the diagram (see the figure). Find the area of the common pasture. | Ivanov <br> 24 ha | Forest | Ermolaev <br> 30 ha | | :--- | :--- | :--- | | Petrov <br> 28 ha | Common <br> pasture | Lake | | E...
1. Consider the field owned by Vasilyev and note that it is 20 hectares, whereas the field owned by Sidorov is 10 hectares. Given that Vasilyev's field is exactly twice the size of Sidorov's, this indicates that the width of Vasilyev's field is also twice that of Sidorov's, assuming the fields are rectangular. 2. Usi...
[ { "content": "\nFarmers Ivanov, Petrov, Sidorov, Vasilev and Ermolaev own rectangular plots of land, the areas of which are indicated in the diagram (see the figure). Find the area of the common pasture.\n\n| Ivanov <br> 24 ha | Forest | Ermolaev <br> 30 ha |\n| :--- | :--- | :--- |\n| Petrov <br> 28 ha | Commo...