cosh() computes the hyperbolic cosine of x.

    cosh(x) is defined as (exp(x) + exp(-x))/2.

                           Entry-Point Names

    Generic                               Compaq
    Function   Data Type   OpenVMS        Tru64 UNIX
    Name       Required    Alpha          Alpha

    cosh       S_FLOAT     math$cosh_s    coshf
               T_FLOAT     math$cosh_t    cosh
               X_FLOAT     math$cosh_x    coshl
               F_FLOAT     math$cosh_f
               G_FLOAT     math$cosh_g