A ball is dropped and its first rebound reaches 20 m. Every next rebound reaches 80% of the previous one. Which rebound n is the first one lower than 0.5 m?
Sequences & series worksheet with answers
1.Easy
a₁ = 20r = 0.8ε = 0.5
n =
2.Easy
Find the sum S of the infinite series Σk=1∞ 9·(−2/5)ᵏ.
a = 9r = −2/5k₀ = 1
S =
3.Medium
Find the sum S = Σk=1∞ 5/(k(k + 3)).
ak = 5/(k(k + 3))
S =
4.Medium
Find the sum S = Σk=1∞ 12/(k(k + 3)).
ak = 12/(k(k + 3))
S =
5.Hard
Recognise the series and find its sum: S = Σk=0∞ (−1)ᵏ·22k+1/(2k + 1)!.
ak = (−1)ᵏ·22k+1/(2k + 1)!
S =
6.Hard
f(x) = sin x is approximated at x = 2 by its Maclaurin polynomial of degree n. With the Lagrange bound M·|x|ⁿ⁺¹/(n + 1)! and M = 1, find the smallest degree n that guarantees an error below 0.001.
f(x) = sin xx = 2M = 1ε = 0.001
n =
Answer key
- 1. n = 18
- 2. S = −2.571
- 3. S = 3.056
- 4. S = 7.333
- 5. S = 0.9093
- 6. n = 9
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