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{
"schemaVersion": 1,
"chapterId": "math-p1-c3",
"slug": "arithmetic-sequences-algebra",
"subject": "maths",
"title": "Arithmetic Sequences and Algebra",
"practiceLabel": "sample",
"source": "SCERT Kerala SSLC Mathematics 2025 raw extract (math-ch3-seqalg-raw.txt). Practice is labelled sample β€” not board-certified.",
"shortNotes": [
"The term at every position is twice the number giving the position:",
"Position 1 2 3 ...",
"Term 2 Γ— 1 = 2 2 Γ— 2 = 4 2 Γ— 3 = 6 ...",
"The term at every position is one less than twice the number giving the position:",
"Term (2 Γ— 1) βˆ’ 1 = 1 (2 Γ— 2) βˆ’ 1 = 3 (2 Γ— 3) βˆ’ 1 = 5 ...",
"We can use algebra to concisely state these.",
"Thus we can describe the first sequence like this:",
"The number in the nth position is 2n",
"The number in the nth position is 2n βˆ’ 1"
],
"definitions": [],
"formulas": [
"Term 2 Γ— 1 = 2 2 Γ— 2 = 4 2 Γ— 3 = 6 ...",
"Term (2 Γ— 1) βˆ’ 1 = 1 (2 Γ— 2) βˆ’ 1 = 3 (2 Γ— 3) βˆ’ 1 = 5 ...",
"The sequence 2, 4, 6, ... of even numbers: xn = 2n",
"The sequence 1, 3, 5, ... of odd numbers: yn = 2n – 1",
"the 10th term is 10 βˆ’ 1 = 9",
"(iv) The 10th term is 12 + (9 Γ— 11) = 111",
"(ii) The nth term is 12 + ((n βˆ’ 1) Γ— 11) = 12 + 11(n βˆ’ 1)",
"11(n βˆ’ 1) = 11n βˆ’ 11",
"12 + 11(n βˆ’ 1) = 12 + (11n βˆ’ 11) = 11n + 1",
"xn = 11n + 1"
],
"commonMistakes": [
"Using the nth-term formula when the question asks for a sum, or the reverse.",
"Skipping the diagram or given data before substituting.",
"Arithmetic slips in substitution after writing the correct formula."
],
"sampleQuestions": [
{
"id": "arithmetic-sequences-algebra-q1",
"marks": 2,
"question": "definite rule. How do we state this rule?",
"answer": "Sample practice β€” write the definition or working from the textbook method.",
"label": "sample"
},
{
"id": "arithmetic-sequences-algebra-q2",
"marks": 2,
"question": "For example, how do we describe the sequence 2, 4, 6, ... of even numbers?",
"answer": "Sample practice β€” write the definition or working from the textbook method.",
"label": "sample"
},
{
"id": "arithmetic-sequences-algebra-q3",
"marks": 2,
"question": "What about the sequence 1, 3, 5, ... of odd numbers?",
"answer": "Sample practice β€” write the definition or working from the textbook method.",
"label": "sample"
},
{
"id": "arithmetic-sequences-algebra-q4",
"marks": 2,
"question": "compute the 10th term of this sequence?",
"answer": "Sample practice β€” write the definition or working from the textbook method.",
"label": "sample"
},
{
"id": "arithmetic-sequences-algebra-q5",
"marks": 2,
"question": "In general how do we write the nth term?",
"answer": "Sample practice β€” write the definition or working from the textbook method.",
"label": "sample"
},
{
"id": "arithmetic-sequences-algebra-q6",
"marks": 2,
"question": "How do we compute its nth term?",
"answer": "Sample practice β€” write the definition or working from the textbook method.",
"label": "sample"
},
{
"id": "arithmetic-sequences-algebra-q7",
"marks": 2,
"question": "adding a fixed number ?",
"answer": "Sample practice β€” write the definition or working from the textbook method.",
"label": "sample"
},
{
"id": "arithmetic-sequences-algebra-q8",
"marks": 2,
"question": "So, what can we say in general?",
"answer": "Sample practice β€” write the definition or working from the textbook method.",
"label": "sample"
}
]
}