The arithmetic sequence −8, −11, −14, −17, … ends with the term −86. How many terms n does it have?
Sequences & series worksheet with answers
1.Easy
a₁ = −8d = −3aₙ = −86
n =
2.Easy
The arithmetic sequence 20, 18, 16, 14, … ends with the term −14. How many terms n does it have?
a₁ = 20d = −2aₙ = −14
n =
3.Medium
Find the sum S = Σk=1∞ 6/(k(k + 3)).
ak = 6/(k(k + 3))
S =
4.Medium
Find the sum S = Σk=1∞ 1/(k(k + 1)).
ak = 1/(k(k + 1))
S =
5.Hard
Recognise the series and find its sum: S = Σk=0∞ (−1)ᵏ·22k+1/(2k + 1)!.
ak = (−1)ᵏ·22k+1/(2k + 1)!
S =
6.Hard
f(x) = sin x is approximated by its Maclaurin polynomial of degree 5 at x = 0.8. 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 = 0.8M = 1
|R₅| =
Answer key
- 1. n = 27
- 2. n = 18
- 3. S = 3.667
- 4. S = 1
- 5. S = 0.9093
- 6. |R₅| = 0.0003641
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