Find the sum S of the infinite series Σk=1∞ 3·(−1/3)ᵏ.
Sequences & series worksheet with answers
1.Easy
a = 3r = −1/3k₀ = 1
S =
2.Easy
Find the term a19 of the arithmetic sequence 15, 20, 25, 30, …
a₁ = 15d = 5n = 19
a19 =
3.Medium
The power series Σk=1∞ k²·4ᵏ·(x − 1)ᵏ converges on an interval around x₀ = 1. Find the right end x of that interval.
Σ k²·4ᵏ·(x − 1)ᵏx₀ = 1
x =
4.Medium
Find the radius of convergence R of the power series Σk=1∞ xᵏ/5ᵏ.
Σ xᵏ/5ᵏx₀ = 0
R =
5.Hard
Find the coefficient c₄ of (x − 1)⁴ in the Taylor series of f(x) = 1/x about a = 1.
f(x) = 1/xa = 1k = 4
c₄ =
6.Hard
Use the Maclaurin polynomial of degree 4 of f(x) = cos(3x) to approximate f(0.5). Give P₄(0.5).
f(x) = cos(3x)n = 4x = 0.5
P₄(0.5) =
Answer key
- 1. S = −0.75
- 2. a19 = 105
- 3. x = 1.25
- 4. R = 5
- 5. c₄ = 1
- 6. P₄(0.5) = 0.08594
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