A ball is dropped and its first rebound reaches 5 m. Every next rebound reaches 80% of the previous one. Which rebound n is the first one lower than 0.01 m?
Sequences & series worksheet with answers
1.Easy
a₁ = 5r = 0.8ε = 0.01
n =
2.Easy
Find the term a21 of the arithmetic sequence −12, −9.5, −7, −4.5, …
a₁ = −12d = 2.5n = 21
a21 =
3.Medium
Find the sum S = Σk=1∞ 5/(k(k + 1)).
ak = 5/(k(k + 1))
S =
4.Medium
Apply the ratio test to Σk=1∞ kᵏ/(3ᵏ·k!). Find L = lim |ak+1/ak|.
ak = kᵏ/(3ᵏ·k!)
L =
5.Hard
Recognise the series and find its sum: S = Σk=0∞ (−1)ᵏ·0.82k+1/(2k + 1)!.
ak = (−1)ᵏ·0.82k+1/(2k + 1)!
S =
6.Hard
Find the coefficient c₂ of (x − 4)² in the Taylor series of f(x) = ln x about a = 4.
f(x) = ln xa = 4k = 2
c₂ =
Answer key
- 1. n = 29
- 2. a21 = 38
- 3. S = 5
- 4. L = 0.9061
- 5. S = 0.7174
- 6. c₂ = −0.03125
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