Find the sum S of the infinite series Σk=2∞ 18·(−1/2)ᵏ.
Sequences & series worksheet with answers
1.Easy
a = 18r = −1/2k₀ = 2
S =
2.Easy
Find the sum S of the infinite series Σk=0∞ 24·(−2/3)ᵏ.
a = 24r = −2/3k₀ = 0
S =
3.Medium
Find the radius of convergence R of the power series Σk=1∞ xᵏ/(k²·5ᵏ).
Σ xᵏ/(k²·5ᵏ)x₀ = 0
R =
4.Medium
Exactly one of the four series diverges. Click it.
A: Σ 5/k³B: Σ 1/(k(k + 2))C: Σ (−1)ᵏ/kD: Σ k!/3ᵏ
- 1A: Σ 5/k³
- 2B: Σ 1/(k(k + 2))
- 3C: Σ (−1)ᵏ/k
- 4D: Σ k!/3ᵏ
5.Hard
f(x) = sin x is approximated at x = 2 by its Maclaurin polynomial of degree n. With the Lagrange bound M·|x|ⁿ⁺¹/(n + 1)! and M = 1, find the smallest degree n that guarantees an error below 1 × 10⁻⁶.
f(x) = sin xx = 2M = 1ε = 1 × 10⁻⁶
n =
6.Hard
Recognise the series and find its sum: S = Σk=0∞ (−1)ᵏ/(2k + 1)!.
ak = (−1)ᵏ/(2k + 1)!
S =
Answer key
- 1. S = 3
- 2. S = 14.4
- 3. R = 5
- 4. D: Σ k!/3ᵏ
- 5. n = 13
- 6. S = 0.8415
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