Find the sum S30 of the first 30 terms of the arithmetic sequence −4, −2.5, −1, 0.5, …
Sequences & series worksheet with answers
1.Easy
a₁ = −4d = 1.5n = 30
S30 =
2.Easy
Find the sum S of the infinite series Σk=2∞ 8·(−1/4)ᵏ.
a = 8r = −1/4k₀ = 2
S =
3.Medium
The power series Σk=1∞ (2k)!·(x + 2)ᵏ/(k!)² converges on an interval around x₀ = −2. Find the left end x of that interval.
Σ (2k)!·(x + 2)ᵏ/(k!)²x₀ = −2
x =
4.Medium
Exactly one of the four series converges. Click it.
A: Σ (k + 3)/k²B: Σ (−1)ᵏ/kC: Σ (3/2)ᵏD: Σ k!/3ᵏ
- 1A: Σ (k + 3)/k²
- 2B: Σ (−1)ᵏ/k
- 3C: Σ (3/2)ᵏ
- 4D: Σ k!/3ᵏ
5.Hard
Find the coefficient c₂ of (x − 2)² in the Taylor series of f(x) = ln x about a = 2.
f(x) = ln xa = 2k = 2
c₂ =
6.Hard
f(x) = eˣ is approximated by its Maclaurin polynomial of degree 2 at x = 0.5. Use the Lagrange error bound M·|x|ⁿ⁺¹/(n + 1)! with M = e0.5 = 1.649 to find the largest possible error |R₂|.
f(x) = eˣn = 2x = 0.5M = 1.649
|R₂| =
Answer key
- 1. S30 = 532.5
- 2. S = 0.4
- 3. x = −2.25
- 4. B: Σ (−1)ᵏ/k
- 5. c₂ = −0.125
- 6. |R₂| = 0.03435
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