Euler’s Formulas

Euler’s formula is our bridge back-and forth between trigonomentric forms ($\cos \theta$ and $\sin \theta$) and complex exponential form ($e^{j\theta }$): $$\begin{array}{rl}{e}^{j\theta }& =\cos \theta +j\sin \theta .\end{array}$$ Here are a few useful identities implied by Euler’s formula. $$\text{Unknown environment 'subequations'}$$