TRIG(3M)                             SysV                             TRIG(3M)



NAME
     trig: sin, cos, tan, asin, acos, atan, atan2 - trigonometric functions

SYNOPSIS
     #include <math.h>

     double sin (x)
     double x;

     double cos (x)
     double x;

     double tan (x)
     double x;

     double asin (x)
     double x;

     double acos (x)
     double x;

     double atan (x)
     double x;

     double atan2 (y, x)
     double y, x;

DESCRIPTION
     sin, cos and tan return respectively the sine, cosine and tangent of
     their argument, x, measured in radians.

     asin returns the arcsine of x, in the range [-pi/2,pi/2].

     acos returns the arccosine of x, in the range [0,pi].

     atan returns the arctangent of x, in the range [-pi/2,pi/2].

     atan2 returns the arctangent of y/x, in the range (-pi,pi], using the
     signs of both arguments to determine the quadrant of the return value.

SEE ALSO
     matherr(3M).

DIAGNOSTICS
     sin, cos, and tan lose accuracy when their argument is far from zero.
     For arguments sufficiently large, these functions return zero when there
     would otherwise be a complete loss of significance.  In this case, and
     only if you have linked your program to /usr/lib/crt0.o, a message
     indicating TLOSS error is printed on the standard error output.  For less
     extreme arguments causing partial loss of significance, a PLOSS error is
     generated but no message is printed.  In both cases, errno is set to
     ERANGE.

     If the magnitude of the argument of asin or acos is greater than one, or
     if both arguments of atan2 are zero, zero is returned and errno is set to
     EDOM.  In addition, if you have linked your program to /usr/lib/crt0.o, a
     message indicating DOMAIN error is printed on the standard error output.

     These error-handling procedures may be changed with the function
     matherr(3M).