[tex]e^{ix}=cosx + isinx [/tex](adsbygoogle = window.adsbygoogle || []).push({});

I know this can be easily proven using the Taylor series, but I recall seeing a proof which doesn't use the Taylor series. I'm pretty sure it has something to do with derivatives, but the problem is I don't remember how it went and I can't find it anywhere. So if anyone knows it or has any idea of where to start could you let me know? Thanks.

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

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

# Proof of complex exponential

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