Cotangent Exponential Formulation

Theorem
Let $z$ be a complex number.

Let $\tan z$ denote the cotangent function and $i$ denote the imaginary unit: $i^2 = -1$.

Then:
 * $\cot z = i \dfrac {e^{i z} + e^{-i z}} {e^{i z} - e^{-i z}}$

Also see

 * Sine Exponential Formulation
 * Cosine Exponential Formulation
 * Tangent Exponential Formulation
 * Secant Exponential Formulation
 * Cosecant Exponential Formulation


 * Arccotangent Logarithmic Formulation