A ball is dropped and its first rebound reaches 2 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 = 2r = 0.8ε = 0.01
n =
2.Easy
The geometric sequence aₙ = 2·0.8ⁿ⁻¹ decreases. Find the first index n for which aₙ < 0.1.
a₁ = 2r = 0.8ε = 0.1
n =
3.Medium
Find the sum S = Σk=1∞ 6/(k(k + 4)).
ak = 6/(k(k + 4))
S =
4.Medium
Find the radius of convergence R of the power series Σk=1∞ 25ᵏx²ᵏ/k.
Σ 25ᵏx²ᵏ/kx₀ = 0
R =
5.Hard
f(x) = eˣ is approximated by its Maclaurin polynomial of degree 5 at x = 1.5. Use the Lagrange error bound M·|x|ⁿ⁺¹/(n + 1)! with M = e1.5 = 4.482 to find the largest possible error |R₅|.
f(x) = eˣn = 5x = 1.5M = 4.482
|R₅| =
6.Hard
f(x) = sin x is approximated by its Maclaurin polynomial of degree 5 at x = 0.3. Use the Lagrange error bound M·|x|ⁿ⁺¹/(n + 1)! with M = 1 to find the largest possible error |R₅|.
f(x) = sin xn = 5x = 0.3M = 1
|R₅| =
Answer key
- 1. n = 25
- 2. n = 15
- 3. S = 3.125
- 4. R = 0.2
- 5. |R₅| = 0.0709
- 6. |R₅| = 1.012 × 10⁻⁶
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