asin

acosh

#include <math.h>float acoshf(float arg);double acosh(double arg); long double acoshl(long double arg);

acosh( ), acoshf( ), and acoshl( ) were added by C99.

The acosh( ) family of functions returns the arc hyperbolic cosine of arg. The argument must be zero or greater; otherwise, a domain error will occur.

Related functions are asinh( ), atanh( ), sinh( ), cosh( ), and tanh( ).