Find the sum S8 of the first 8 terms of the arithmetic sequence 20, 25, 30, 35, …
Sequences & series worksheet with answers
1.Easy
a₁ = 20d = 5n = 8
S8 =
2.Easy
Find the sum S of the infinite series Σk=1∞ 2·(1/2)ᵏ.
a = 2r = 1/2k₀ = 1
S =
3.Medium
Find the sum S = Σk=1∞ 1/(k(k + 4)).
ak = 1/(k(k + 4))
S =
4.Medium
Find the sum S = Σk=1∞ 3/(k(k + 2)).
ak = 3/(k(k + 2))
S =
5.Hard
f(x) = sin x is approximated at x = 2 by its Maclaurin polynomial of degree n. With the Lagrange bound M·|x|ⁿ⁺¹/(n + 1)! and M = 1, find the smallest degree n that guarantees an error below 0.0001.
f(x) = sin xx = 2M = 1ε = 0.0001
n =
6.Hard
f(x) = cos x is approximated at x = 1 by its Maclaurin polynomial of degree n. With the Lagrange bound M·|x|ⁿ⁺¹/(n + 1)! and M = 1, find the smallest degree n that guarantees an error below 0.001.
f(x) = cos xx = 1M = 1ε = 0.001
n =
Answer key
- 1. S8 = 300
- 2. S = 2
- 3. S = 0.5208
- 4. S = 2.25
- 5. n = 10
- 6. n = 6
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