Secant of i

Theorem

 * $\sec i = \dfrac {2 e} {e^2 + 1}$

where $\sec$ denotes the complex secant function and $i$ is the imaginary unit.

Also see

 * Sine of $i$
 * Cosine of $i$
 * Tangent of $i$
 * Cotangent of $i$
 * Cosecant of $i$