Some time ago I was looking for an easy way to put some math writing within my Evernote notes trough my Mac device. Even if there is no official solution to the problem and the feature request is still pending within Evernote dedicated forum, I finally came out with a very simple way to solve your problem out.
This way is called Grapher, a Mac OS built-in application for visualising math stuffs.
Here below a simple tutorial:
1. find Grapher among your applications
You can either search for it within Spotlight or using the launchpad.
3. copy the equation as TIFF
4. paste the equation into Evernote
And that’s it!
I think this trick is very useful when you have some “heavy” equations that would not be clear enough if it would just be written in simple text.