Find the sum S35 of the first 35 terms of the arithmetic sequence 7, 4, 1, −2, …
Sequences & series worksheet with answers
1.Easy
a₁ = 7d = −3n = 35
S35 =
2.Easy
Find the sum S9 of the first 9 terms of the geometric sequence 10, 5, 2.5, …
a₁ = 10r = 0.5n = 9
S9 =
3.Medium
Exactly one of the four series converges. Click it.
A: Σ (−1)ᵏ/kB: Σ 3ᵏ/k²C: Σ 3/kD: Σ ln k / k
- 1A: Σ (−1)ᵏ/k
- 2B: Σ 3ᵏ/k²
- 3C: Σ 3/k
- 4D: Σ ln k / k
4.Medium
Find the sum S = Σk=1∞ 12/(k(k + 2)).
ak = 12/(k(k + 2))
S =
5.Hard
Recognise the series and find its sum: S = Σk=1∞ k·0.5ᵏ.
ak = k·0.5ᵏ
S =
6.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 0.0001.
f(x) = sin xx = 2M = 1ε = 0.0001
n =
Answer key
- 1. S35 = −1540
- 2. S9 = 19.96
- 3. A: Σ (−1)ᵏ/k
- 4. S = 9
- 5. S = 2
- 6. n = 10
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