Find the term a22 of the arithmetic sequence 4, 6.5, 9, 11.5, …
Sequences & series worksheet with answers
1.Easy
a₁ = 4d = 2.5n = 22
a22 =
2.Easy
Find the sum S20 of the first 20 terms of the arithmetic sequence 3, 8, 13, 18, …
a₁ = 3d = 5n = 20
S20 =
3.Medium
Find the radius of convergence R of the power series Σk=1∞ k²·3ᵏ·xᵏ.
Σ k²·3ᵏ·xᵏx₀ = 0
R =
4.Medium
Exactly one of the four series diverges. Click it.
A: Σ ln k / kB: Σ 5ᵏ/k!C: Σ 3/k³D: Σ (2/3)ᵏ
- 1A: Σ ln k / k
- 2B: Σ 5ᵏ/k!
- 3C: Σ 3/k³
- 4D: Σ (2/3)ᵏ
5.Hard
Recognise the series and find its sum: S = Σk=1∞ (−1)k+1/k.
ak = (−1)k+1/k
S =
6.Hard
Use the Maclaurin polynomial of degree 4 of f(x) = e3x to approximate f(0.8). Give P₄(0.8).
f(x) = e3xn = 4x = 0.8
P₄(0.8) =
Answer key
- 1. a22 = 56.5
- 2. S20 = 1010
- 3. R = 0.3333
- 4. A: Σ ln k / k
- 5. S = 0.6931
- 6. P₄(0.8) = 9.966
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