Find the sum S of the infinite series Σk=1∞ 12·(2/5)ᵏ.
Sequences & series worksheet with answers
1.Easy
a = 12r = 2/5k₀ = 1
S =
2.Easy
Find the sum S15 of the first 15 terms of the arithmetic sequence 7, 9, 11, 13, …
a₁ = 7d = 2n = 15
S15 =
3.Medium
Exactly one of the four series converges. Click it.
A: Σ (3k + 1)/(k + 2)B: Σ ln k / kC: Σ (3/2)ᵏD: Σ k²/2ᵏ
- 1A: Σ (3k + 1)/(k + 2)
- 2B: Σ ln k / k
- 3C: Σ (3/2)ᵏ
- 4D: Σ k²/2ᵏ
4.Medium
Exactly one of the four series diverges. Click it.
A: Σ (2/3)ᵏB: Σ k³/2ᵏC: Σ 2/k⁴D: Σ 2ᵏ/k²
- 1A: Σ (2/3)ᵏ
- 2B: Σ k³/2ᵏ
- 3C: Σ 2/k⁴
- 4D: Σ 2ᵏ/k²
5.Hard
f(x) = ln(1 + x) is approximated by its Maclaurin polynomial of degree 5 at x = 0.2. Use the Lagrange error bound M·|x|ⁿ⁺¹/(n + 1)! with M = 5! = 120 to find the largest possible error |R₅|.
f(x) = ln(1 + x)n = 5x = 0.2M = 120
|R₅| =
6.Hard
f(x) = sin x is approximated by its Maclaurin polynomial of degree 2 at x = 1.5. Use the Lagrange error bound M·|x|ⁿ⁺¹/(n + 1)! with M = 1 to find the largest possible error |R₂|.
f(x) = sin xn = 2x = 1.5M = 1
|R₂| =
Answer key
- 1. S = 8
- 2. S15 = 315
- 3. D: Σ k²/2ᵏ
- 4. D: Σ 2ᵏ/k²
- 5. |R₅| = 1.067 × 10⁻⁵
- 6. |R₂| = 0.5625
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