Why is it that when I do integration by parts on cyclic functions such as (sinx)e^(inx), I get a trivial answer like C=C, C is a constant(adsbygoogle = window.adsbygoogle || []).push({});

Have I done something wrong or are there other methods of doing those integrals?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Trivial integration by parts?

**Physics Forums | Science Articles, Homework Help, Discussion**