A ball is dropped and its first rebound reaches 10 m. Every next rebound reaches 90% of the previous one. Which rebound n is the first one lower than 0.1 m?
Sequences & series worksheet with answers
1.Easy
a₁ = 10r = 0.9ε = 0.1
n =
2.Easy
Find the term a27 of the arithmetic sequence 19, 19.5, 20, 20.5, …
a₁ = 19d = 0.5n = 27
a27 =
3.Medium
Find the sum S = Σk=1∞ 4/(k(k + 4)).
ak = 4/(k(k + 4))
S =
4.Medium
Exactly one of the four series diverges. Click it.
A: Σ (−1)ᵏ/kB: Σ 3ᵏ/k!C: Σ 1/√kD: Σ (2/5)ᵏ
- 1A: Σ (−1)ᵏ/k
- 2B: Σ 3ᵏ/k!
- 3C: Σ 1/√k
- 4D: Σ (2/5)ᵏ
5.Hard
Recognise the series and find its sum: S = Σk=0∞ (−1)ᵏ·0.52k/(2k)!.
ak = (−1)ᵏ·0.52k/(2k)!
S =
6.Hard
Recognise the series and find its sum: S = Σk=1∞ k·0.5ᵏ.
ak = k·0.5ᵏ
S =
Answer key
- 1. n = 45
- 2. a27 = 32
- 3. S = 2.083
- 4. C: Σ 1/√k
- 5. S = 0.8776
- 6. S = 2
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