Hyperbolic Function

Also, see their relationship to even/odd functions. Hyperbolic trig functions are parameterizing the exponential functions:

  • $e^x$ and $e^{-x}$ => $\cosh(x)$, $\sinh(x)$
  • imaginary exponential function ( $e^{ix}$ and $e^{-ix}$ ) => $\cos(x), \sin(x)$ .