Bell 32V development

[unix-history] / usr / src / libnm / acos.c

/*
acos(arg) return the arccos,
       respectively of their arguments.

       Arctan is called after appropriate range reduction.
*/

#include        <errno.h>
int errno;
double atan();
double sqrt();
static double pio2      = 1.570796326794896619;

double
acos(arg) double arg; {

       if(arg < 0)
               arg = -arg;

       if(arg > 1.){
               errno = EDOM;
               return(0.);
       }

       return(pio2 - asin(arg));
}