A ball is dropped and its first rebound reaches 8 m. Every next rebound reaches 70% of the previous one. Which rebound n is the first one lower than 0.1 m?
Sequences & series worksheet with answers
1.Easy
a₁ = 8r = 0.7ε = 0.1
n =
2.Easy
Find the sum S6 of the first 6 terms of the geometric sequence 5, 2.5, 1.25, …
a₁ = 5r = 0.5n = 6
S6 =
3.Medium
Apply the ratio test to Σk=1∞ kᵏ/(2ᵏ·k!). Find L = lim |ak+1/ak|.
ak = kᵏ/(2ᵏ·k!)
L =
4.Medium
Find the sum S = Σk=1∞ 6/(k(k + 4)).
ak = 6/(k(k + 4))
S =
5.Hard
Recognise the series and find its sum: S = Σk=0∞ (−1)ᵏ·22k/(2k)!.
ak = (−1)ᵏ·22k/(2k)!
S =
6.Hard
f(x) = cos x is approximated at x = 1 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 1 × 10⁻⁶.
f(x) = cos xx = 1M = 1ε = 1 × 10⁻⁶
n =
Answer key
- 1. n = 14
- 2. S6 = 9.844
- 3. L = 1.359
- 4. S = 3.125
- 5. S = −0.4161
- 6. n = 9
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