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Grade 12 · Number Patterns, Sequences and Series
Series, Sigma Notation & Convergence (Grade 12)
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/ 29
Answer all questions. Show all your working — marks are awarded for method as well as the final answer.
- 1The general term of an arithmetic sequence is Tₙ = 2n + 4. Determine T₁₀.(1)
- 2Determine the sum of the first 19 terms of Tₙ = 2n + 4.(3)
- 3Evaluate ∑n=120 (3n − 1)(3)
- 4How many terms are there in ∑n=310 Tₙ?(1)
- 5Write 2 + 5 + 8 + … + 59 in sigma notation.(3)
- 6Determine S∞ for 8 + 4 + 2 + 1 + …(2)
- 7Determine the values of x for which ∑ 3(2x)n − 1 converges.(3)
- 8Calculate S₁₀ for the geometric series 2 + 6 + 18 + …(3)
- 9Derive the formula Sₙ = n/2 (a + l) for an arithmetic series.(4)
- 10Derive the formula for the sum of the first n terms of a geometric series.(4)
- 11Explain why the sum to infinity only exists when −1 < r < 1.(2)
TOTAL: 29 marks