The
COSH function returns the hyperbolic cosine of *
X*
.

The value for which the hyperbolic cosine is desired, specified in radians. If *
X*
is double-precision floating, the result is also double- precision. Complex values are not allowed. All other types are converted to single-precision floating-point and yield floating-point results. COSH is defined as:

COSH(*
u*
) = (*
eu*
+ *
e*
^{
-}
*
u*
) / 2

If *
X*
is an array, the result has the same structure, with each element containing the hyperbolic cosine of the corresponding element of *
X*
.