A ball is dropped and its first rebound reaches 10 m. Every next rebound reaches 75% of the previous one. Which rebound n is the first one lower than 0.5 m?
Sequences & series worksheet with answers
1.Easy
a₁ = 10r = 0.75ε = 0.5
n =
2.Easy
Find the sum S7 of the first 7 terms of the geometric sequence 1, 3, 9, …
a₁ = 1r = 3n = 7
S7 =
3.Medium
Find the radius of convergence R of the power series Σk=1∞ (2k)!·xᵏ/(k!)².
Σ (2k)!·xᵏ/(k!)²x₀ = 0
R =
4.Medium
Apply the ratio test to Σk=1∞ k!/kᵏ. Find L = lim |ak+1/ak|.
ak = k!/kᵏ
L =
5.Hard
Use the Maclaurin polynomial of degree 4 of f(x) = 1/(1 − x) to approximate f(0.5). Give P₄(0.5).
f(x) = 1/(1 − x)n = 4x = 0.5
P₄(0.5) =
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 0.0005.
f(x) = cos xx = 1M = 1ε = 0.0005
n =
Answer key
- 1. n = 12
- 2. S7 = 1093
- 3. R = 0.25
- 4. L = 0.3679
- 5. P₄(0.5) = 1.938
- 6. n = 6
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