Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

I want to show that if $a_{n}\downarrow 0$ and $na_{n}=O(1)$ then $\displaystyle \sum_{n=1}^{\infty}a_{n}\sin nx$ is a Fourier series of $f\in L^{\infty}$. Can anybody help me?

share|improve this question
    
First, you can show with a Abel transform that the series is converging for all $x$. –  Davide Giraudo May 1 '12 at 9:09
add comment

Know someone who can answer? Share a link to this question via email, Google+, Twitter, or Facebook.

Your Answer

 
discard

By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.