The arithmetic sequence 10, 6, 2, −2, … ends with the term −26. How many terms n does it have?
Sequences & series worksheet with answers
1.Easy
a₁ = 10d = −4aₙ = −26
n =
2.Easy
Find the sum S of the infinite series Σk=2∞ 8·(3/4)ᵏ.
a = 8r = 3/4k₀ = 2
S =
3.Medium
Find the sum S = Σk=1∞ 1/(k(k + 4)).
ak = 1/(k(k + 4))
S =
4.Medium
Exactly one of the four series converges. Click it.
A: Σ 1/√kB: Σ k³/2ᵏC: Σ (3/2)ᵏD: Σ k!/2ᵏ
- 1A: Σ 1/√k
- 2B: Σ k³/2ᵏ
- 3C: Σ (3/2)ᵏ
- 4D: Σ k!/2ᵏ
5.Hard
f(x) = sin x is approximated by its Maclaurin polynomial of degree 4 at x = 0.3. Use the Lagrange error bound M·|x|ⁿ⁺¹/(n + 1)! with M = 1 to find the largest possible error |R₄|.
f(x) = sin xn = 4x = 0.3M = 1
|R₄| =
6.Hard
f(x) = cos x is approximated by its Maclaurin polynomial of degree 4 at x = 1. Use the Lagrange error bound M·|x|ⁿ⁺¹/(n + 1)! with M = 1 to find the largest possible error |R₄|.
f(x) = cos xn = 4x = 1M = 1
|R₄| =
Answer key
- 1. n = 10
- 2. S = 18
- 3. S = 0.5208
- 4. B: Σ k³/2ᵏ
- 5. |R₄| = 2.025 × 10⁻⁵
- 6. |R₄| = 0.008333
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