Trig and Hyperbolic Functions

Hyperbolic in terms of trig #

$\cosh(z)=\cos(iz)$ $\sinh(z)=-i\sin(iz)$

Trig in terms of Hyperbolic #

$\cos(z)=\cosh(iz)$ $\sin(z)=-i\sinh(iz)$

Inverse of sinh and cosh in terms of ln #

$\cosh^{-1}(x)=ln(x+\sqrt{x^2-1})$ $\sinh^{-1}(x)=ln(x+\sqrt{x^2+1})$