Find the sum S33 of the first 33 terms of the arithmetic sequence 12, 10, 8, 6, …
Sequences & series worksheet with answers
1.Easy
a₁ = 12d = −2n = 33
S33 =
2.Easy
The geometric sequence aₙ = 5·0.8ⁿ⁻¹ decreases. Find the first index n for which aₙ < 0.1.
a₁ = 5r = 0.8ε = 0.1
n =
3.Medium
Apply the ratio test to Σk=1∞ (k!)²·8ᵏ/(2k)!. Find L = lim |ak+1/ak|.
ak = (k!)²·8ᵏ/(2k)!
L =
4.Medium
Apply the ratio test to Σk=1∞ kᵏ/(3ᵏ·k!). Find L = lim |ak+1/ak|.
ak = kᵏ/(3ᵏ·k!)
L =
5.Hard
f(x) = sin 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 0.0005.
f(x) = sin xx = 1M = 1ε = 0.0005
n =
6.Hard
Find the coefficient c₂ of (x − 1)² in the Taylor series of f(x) = ∛x about a = 1.
f(x) = ∛xa = 1k = 2
c₂ =
Answer key
- 1. S33 = −660
- 2. n = 19
- 3. L = 2
- 4. L = 0.9061
- 5. n = 6
- 6. c₂ = −0.1111
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