acosh(p1)
public
Computes the inverse hyperbolic cosine of x.
static VALUE
math_acosh(VALUE obj, VALUE x)
{
double d0, d;
Need_Float(x);
d0 = RFLOAT_VALUE(x);
/* check for domain error */
if (d0 < 1.0) domain_error("acosh");
d = acosh(d0);
return DBL2NUM(d);
}
