There's a small typo in just after the title "Euler's Formula". You say that you can write z as x=iy but it must be x+iy. Nothing serious but may affect the novices...

## Typo

There's a small typo in just after the title "Euler's Formula". You say that you can write z as x=iy but it must be x+iy.

Nothing serious but may affect the novices...