Tangent of i

Theorem

 * $\tan i = \left({\dfrac {e^2 - 1} {e^2 + 1} }\right) i$

where $\tan$ denotes the complex tangent function and $i$ is the imaginary unit.

Also see

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