The arithmetic sequence −4, −3.5, −3, −2.5, … ends with the term 14.5. How many terms n does it have?
Sequences & series worksheet with answers
1.Easy
a₁ = −4d = 0.5aₙ = 14.5
n =
2.Easy
The arithmetic sequence −12, −8, −4, 0, … ends with the term 72. How many terms n does it have?
a₁ = −12d = 4aₙ = 72
n =
3.Medium
Find the radius of convergence R of the power series Σk=1∞ xᵏ/2ᵏ.
Σ xᵏ/2ᵏx₀ = 0
R =
4.Medium
Find the radius of convergence R of the power series Σk=1∞ k!·xᵏ/kᵏ.
Σ k!·xᵏ/kᵏx₀ = 0
R =
5.Hard
Recognise the series and find its sum: S = Σk=0∞ 1.5ᵏ/k!.
ak = 1.5ᵏ/k!
S =
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. n = 38
- 2. n = 22
- 3. R = 2
- 4. R = 2.718
- 5. S = 4.482
- 6. c₂ = −0.125
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