A ball is dropped and its first rebound reaches 8 m. Every next rebound reaches 60% of the previous one. Which rebound n is the first one lower than 0.2 m?
Sequences & series worksheet with answers
1.Easy
a₁ = 8r = 0.6ε = 0.2
n =
2.Easy
The geometric sequence aₙ = 8·0.7ⁿ⁻¹ decreases. Find the first index n for which aₙ < 0.1.
a₁ = 8r = 0.7ε = 0.1
n =
3.Medium
Find the radius of convergence R of the power series Σk=1∞ 25ᵏx²ᵏ/k.
Σ 25ᵏx²ᵏ/kx₀ = 0
R =
4.Medium
Find the radius of convergence R of the power series Σk=1∞ k·5ᵏ·xᵏ.
Σ k·5ᵏ·xᵏx₀ = 0
R =
5.Hard
Recognise the series and find its sum: S = Σk=1∞ (−1)k+1·0.75ᵏ/k.
ak = (−1)k+1·0.75ᵏ/k
S =
6.Hard
Recognise the series and find its sum: S = Σk=1∞ (−1)k+1/k.
ak = (−1)k+1/k
S =
Answer key
- 1. n = 9
- 2. n = 14
- 3. R = 0.2
- 4. R = 0.2
- 5. S = 0.5596
- 6. S = 0.6931
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