Sine Exponential Formulation

Theorem
For any complex number $x$,
 * $ \displaystyle \sin x = \frac 1 2 i \left({ e^{-i x} - e^{i x} }\right)$

where $\sin x$ is the sine and $i^2 = -1$.

Also see

 * Cosine Exponential Formulation
 * Tangent Exponential Formulation