# A simpler demo of Euler’s formula

Following on from yesterday I found the following at:
http://www.proofwiki.org/wiki/Euler’s_Formula

Differentiate $\displaystyle\frac{\cos\theta + i\sin\theta}{e^{i\theta}}$ to get zero. Then put $\theta=0$ to show that the constant value of $\displaystyle\frac{\cos\theta + i\sin\theta}{e^{i\theta}}$ must be $1$.

That’s it!