Find the sum S7 of the first 7 terms of the geometric sequence 1, 1.2, 1.44, …
Sequences & series worksheet with answers
1.Easy
a₁ = 1r = 1.2n = 7
S7 =
2.Easy
Find the sum S5 of the first 5 terms of the geometric sequence 0.5, −1, 2, …
a₁ = 0.5r = −2n = 5
S5 =
3.Medium
Find the radius of convergence R of the power series Σk=1∞ k·4ᵏ·(x − 1)ᵏ.
Σ k·4ᵏ·(x − 1)ᵏx₀ = 1
R =
4.Medium
Exactly one of the four series diverges. Click it.
A: Σ 1/k³B: Σ k³/5ᵏC: Σ (4k + 1)/(k + 2)D: Σ (1/2)ᵏ
- 1A: Σ 1/k³
- 2B: Σ k³/5ᵏ
- 3C: Σ (4k + 1)/(k + 2)
- 4D: Σ (1/2)ᵏ
5.Hard
Find the coefficient c₃ of (x − 2)³ in the Taylor series of f(x) = ln x about a = 2.
f(x) = ln xa = 2k = 3
c₃ =
6.Hard
Recognise the series and find its sum: S = Σk=0∞ (−1)ᵏ/(2k)!.
ak = (−1)ᵏ/(2k)!
S =
Answer key
- 1. S7 = 12.92
- 2. S5 = 5.5
- 3. R = 0.25
- 4. C: Σ (4k + 1)/(k + 2)
- 5. c₃ = 0.04167
- 6. S = 0.5403
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