Find the sum S9 of the first 9 terms of the geometric sequence 0.5, −1.5, 4.5, …
Sequences & series worksheet with answers
1.Easy
a₁ = 0.5r = −3n = 9
S9 =
2.Easy
Find the sum S of the infinite series Σk=0∞ 10·(2/5)ᵏ.
a = 10r = 2/5k₀ = 0
S =
3.Medium
Find the radius of convergence R of the power series Σk=1∞ (2k)!·(x + 2)ᵏ/(k!)².
Σ (2k)!·(x + 2)ᵏ/(k!)²x₀ = −2
R =
4.Medium
Exactly one of the four series converges. Click it.
A: Σ (3/5)ᵏB: Σ (7/4)ᵏC: Σ (k + 3)/k²D: Σ 1/(4k + 2)
- 1A: Σ (3/5)ᵏ
- 2B: Σ (7/4)ᵏ
- 3C: Σ (k + 3)/k²
- 4D: Σ 1/(4k + 2)
5.Hard
Find the coefficient c₂ of (x − 2)² in the Taylor series of f(x) = e−x about a = 2.
f(x) = e−xa = 2k = 2
c₂ =
6.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 =
Answer key
- 1. S9 = 2461
- 2. S = 16.67
- 3. R = 0.25
- 4. A: Σ (3/5)ᵏ
- 5. c₂ = 0.06767
- 6. c₃ = 0.04167
Full step-by-step solutions: practise this topic on examproblems.com.