Find the sum S17 of the first 17 terms of the arithmetic sequence −12, −7, −2, 3, …
Sequences & series worksheet with answers
1.Easy
a₁ = −12d = 5n = 17
S17 =
2.Easy
Find the sum S of the infinite series Σk=1∞ 8·(−1/3)ᵏ.
a = 8r = −1/3k₀ = 1
S =
3.Medium
Exactly one of the four series diverges. Click it.
A: Σ k²/5ᵏB: Σ 1/(k² + 5)C: Σ 5/kD: Σ (−1)ᵏ/√k
- 1A: Σ k²/5ᵏ
- 2B: Σ 1/(k² + 5)
- 3C: Σ 5/k
- 4D: Σ (−1)ᵏ/√k
4.Medium
Apply the ratio test to Σk=1∞ 2ᵏ·k!/kᵏ. Find L = lim |ak+1/ak|.
ak = 2ᵏ·k!/kᵏ
L =
5.Hard
f(x) = eˣ is approximated at x = 0.5 by its Maclaurin polynomial of degree n. With the Lagrange bound M·|x|ⁿ⁺¹/(n + 1)! and M = 2, find the smallest degree n that guarantees an error below 1 × 10⁻⁵.
f(x) = eˣx = 0.5M = 2ε = 1 × 10⁻⁵
n =
6.Hard
Find the coefficient c₄ of (x − 1)⁴ in the Taylor series of f(x) = ln x about a = 1.
f(x) = ln xa = 1k = 4
c₄ =
Answer key
- 1. S17 = 476
- 2. S = −2
- 3. C: Σ 5/k
- 4. L = 0.7358
- 5. n = 6
- 6. c₄ = −0.25
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