Find the sum S of the infinite series Σk=1∞ 10·(2/5)ᵏ.
Sequences & series worksheet with answers
1.Easy
a = 10r = 2/5k₀ = 1
S =
2.Easy
Find the sum S of the infinite series Σk=2∞ 4·(1/2)ᵏ.
a = 4r = 1/2k₀ = 2
S =
3.Medium
Find the sum S = Σk=1∞ 3/(k(k + 2)).
ak = 3/(k(k + 2))
S =
4.Medium
Find the radius of convergence R of the power series Σk=1∞ 25ᵏx²ᵏ/k.
Σ 25ᵏx²ᵏ/kx₀ = 0
R =
5.Hard
f(x) = cos x is approximated by its Maclaurin polynomial of degree 5 at x = 1. Use the Lagrange error bound M·|x|ⁿ⁺¹/(n + 1)! with M = 1 to find the largest possible error |R₅|.
f(x) = cos xn = 5x = 1M = 1
|R₅| =
6.Hard
Recognise the series and find its sum: S = Σk=0∞ (−1)ᵏ·22k/(2k)!.
ak = (−1)ᵏ·22k/(2k)!
S =
Answer key
- 1. S = 6.667
- 2. S = 2
- 3. S = 2.25
- 4. R = 0.2
- 5. |R₅| = 0.001389
- 6. S = −0.4161
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