Find the sum S5 of the first 5 terms of the geometric sequence 3, 4.5, 6.75, …
Sequences & series worksheet with answers
1.Easy
a₁ = 3r = 1.5n = 5
S5 =
2.Easy
The arithmetic sequence 1, −1, −3, −5, … ends with the term −57. How many terms n does it have?
a₁ = 1d = −2aₙ = −57
n =
3.Medium
Find the sum S = Σk=16 3/(k(k + 1)).
ak = 3/(k(k + 1))n = 6
S =
4.Medium
Find the radius of convergence R of the power series Σk=1∞ xᵏ/(k·4ᵏ).
Σ xᵏ/(k·4ᵏ)x₀ = 0
R =
5.Hard
Use the Maclaurin polynomial of degree 3 of f(x) = 1/(1 + x) to approximate f(−0.4). Give P₃(−0.4).
f(x) = 1/(1 + x)n = 3x = −0.4
P₃(−0.4) =
6.Hard
Find the coefficient c₂ of (x − 1)² in the Taylor series of f(x) = ∛x about a = 1.
f(x) = ∛xa = 1k = 2
c₂ =
Answer key
- 1. S5 = 39.56
- 2. n = 30
- 3. S = 2.571
- 4. R = 4
- 5. P₃(−0.4) = 1.624
- 6. c₂ = −0.1111
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