Find the sum S10 of the first 10 terms of the geometric sequence 10, 15, 22.5, …
Sequences & series worksheet with answers
1.Easy
a₁ = 10r = 1.5n = 10
S10 =
2.Easy
A ball is dropped and its first rebound reaches 8 m. Every next rebound reaches 85% of the previous one. Which rebound n is the first one lower than 0.5 m?
a₁ = 8r = 0.85ε = 0.5
n =
3.Medium
Find the sum S = Σk=1∞ 1/(k(k + 2)).
ak = 1/(k(k + 2))
S =
4.Medium
Find the sum S = Σk=1∞ 4/(k(k + 3)).
ak = 4/(k(k + 3))
S =
5.Hard
Recognise the series and find its sum: S = Σk=0∞ (−1)ᵏ·1.22k/(2k)!.
ak = (−1)ᵏ·1.22k/(2k)!
S =
6.Hard
Find the coefficient c₃ of (x + 1)³ in the Taylor series of f(x) = e3x about a = −1.
f(x) = e3xa = −1k = 3
c₃ =
Answer key
- 1. S10 = 1133
- 2. n = 19
- 3. S = 0.75
- 4. S = 2.444
- 5. S = 0.3624
- 6. c₃ = 0.224
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