Hi everybody,(adsbygoogle = window.adsbygoogle || []).push({});

I read that sin(2x) and sin(3x) are orthogonal to each other.

In general if I want to check if two functions are orthogonal or not I must integrate their product

First: why the integration of their multiplication (not their addition for example)?

Second: Orthogonal means Perpendicular. But I can't figure out how sin(2x) and sin(3x) are perpendicular

Thank you for your help

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

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

# Sin(2x) and sin(3x) are orthogonal to each other

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