The arithmetic sequence 11, 11.5, 12, 12.5, … ends with the term 16. How many terms n does it have?
Sequences & series worksheet with answers
1.Easy
a₁ = 11d = 0.5aₙ = 16
n =
2.Easy
A ball is dropped and its first rebound reaches 3 m. Every next rebound reaches 90% of the previous one. Which rebound n is the first one lower than 0.2 m?
a₁ = 3r = 0.9ε = 0.2
n =
3.Medium
Exactly one of the four series diverges. Click it.
A: Σ (5k + 1)/(k + 2)B: Σ (4/5)ᵏC: Σ 5/k²D: Σ 1/(k² + 1)
- 1A: Σ (5k + 1)/(k + 2)
- 2B: Σ (4/5)ᵏ
- 3C: Σ 5/k²
- 4D: Σ 1/(k² + 1)
4.Medium
Apply the ratio test to Σk=1∞ 3ᵏ·k!/kᵏ. Find L = lim |ak+1/ak|.
ak = 3ᵏ·k!/kᵏ
L =
5.Hard
Find the coefficient c₂ of (x + 1)² in the Taylor series of f(x) = e3x about a = −1.
f(x) = e3xa = −1k = 2
c₂ =
6.Hard
Recognise the series and find its sum: S = Σk=1∞ (−1)k+1·0.25ᵏ/k.
ak = (−1)k+1·0.25ᵏ/k
S =
Answer key
- 1. n = 11
- 2. n = 27
- 3. A: Σ (5k + 1)/(k + 2)
- 4. L = 1.104
- 5. c₂ = 0.224
- 6. S = 0.2231
Full step-by-step solutions: practise this topic on examproblems.com.