1.6 asinh, asinhf—inverse hyperbolic sine

Synopsis

#include <math.h>
double asinh(double x);
float asinhf(float x);

Description
asinh calculates the inverse hyperbolic sine of x. asinh is defined as

 sgn(x) * log(abs(x) + sqrt(1+x*x))

asinhf is identical, other than taking and returning floats.

Returns
asinh and asinhf return the calculated value.

Portability
Neither asinh nor asinhf are ANSI C.