netbsd man page for acosh

ACOSH(3)						   BSD Library Functions Manual 						  ACOSH(3)

NAME
     acosh, acoshf -- inverse hyperbolic cosine function

LIBRARY
     Math Library (libm, -lm)

SYNOPSIS
     #include <math.h>

     double
     acosh(double x);

     float
     acoshf(float x);

DESCRIPTION
     The acosh() and acoshf() functions compute the inverse hyperbolic cosine of the real argument x.

RETURN VALUES
     If x is less than one, acosh(x) and acoshf(x) return NaN and set the global variable errno to EDOM.

SEE ALSO
     asinh(3), atanh(3), exp(3), math(3)

HISTORY
     The acosh() function appeared in 4.3BSD.

BSD
								    May 6, 1991 							       BSD