Series calculus

Calculus Level 2

DOES IT CONVERGES(ABSOLUTELY)?

NO NOT AT ALL YES MAYBE

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2 solutions

David Vreken
Jul 20, 2020

See here .

Since ( 1 ) n sin ( n ) n 2 = sin ( n ) n 2 1 n 2 \displaystyle |(-1)^n\frac{\sin(n)}{n^2}| = |\frac{\sin(n)}{n^2}| \leq \frac{1}{n^2} , and since n = 1 1 n 2 \displaystyle \sum_{n=1}^{\infty}\frac{1}{n^2} converges to π 2 6 \displaystyle\frac{\pi^2}{6} , then by the comparison test n = 1 ( 1 ) n sin ( n ) n 2 \displaystyle \sum_{n=1}^{\infty}(-1)^n\frac{\sin(n)}{n^2} must absolutely converge, too.

No and Not at all are same, Maybe is never the correct answer. But I want to know how to solve it.

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see here

David Vreken - 10 months, 3 weeks ago

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Thanks a lot, Sir! Please write a solution with this link, so that I can upvote Helpful :)

Vinayak Srivastava - 10 months, 3 weeks ago

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