Find the term a17 of the arithmetic sequence −5, −8, −11, −14, …
Sequences & series worksheet with answers
1.Easy
a₁ = −5d = −3n = 17
a17 =
2.Easy
Find the sum S5 of the first 5 terms of the geometric sequence 4, 4.8, 5.76, …
a₁ = 4r = 1.2n = 5
S5 =
3.Medium
Exactly one of the four series diverges. Click it.
A: Σ 2/k⁴B: Σ ln k / kC: Σ (4/5)ᵏD: Σ 1/(2ᵏ + k)
- 1A: Σ 2/k⁴
- 2B: Σ ln k / k
- 3C: Σ (4/5)ᵏ
- 4D: Σ 1/(2ᵏ + k)
4.Medium
Find the sum S = Σk=1∞ 2/(k(k + 4)).
ak = 2/(k(k + 4))
S =
5.Hard
f(x) = sin x is approximated by its Maclaurin polynomial of degree 4 at x = 1.5. Use the Lagrange error bound M·|x|ⁿ⁺¹/(n + 1)! with M = 1 to find the largest possible error |R₄|.
f(x) = sin xn = 4x = 1.5M = 1
|R₄| =
6.Hard
Recognise the series and find its sum: S = Σk=0∞ (−1)ᵏ·1.22k/(2k)!.
ak = (−1)ᵏ·1.22k/(2k)!
S =
Answer key
- 1. a17 = −53
- 2. S5 = 29.77
- 3. B: Σ ln k / k
- 4. S = 1.042
- 5. |R₄| = 0.06328
- 6. S = 0.3624
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