Returns the hyperbolic cosine of its radian argument.

    Format

      #include  <math.h>

      double cosh  (double x);

      float coshf  (float x); (Integrity servers, Alpha)

      long double coshl  (long double x); (Integrity servers, Alpha)

1 - Argument

 x

    A radian expressed as a real number.

2 - Description

    The cosh functions return the hyperbolic cosine of x and are
    defined as (e**x + e**(-x))/2.

3 - Return Values

    x                  The hyperbolic cosine of the argument.
    HUGE_VAL           Indicates that the argument is too large;
                       errno is set to ERANGE.