Man Page asinpi.3m




NAME

     trig_sun, sincos, sind, cosd,  tand,  asind,  acosd,  atand,
     atan2d, sincosd, sinp, cosp, tanp, asinp, acosp, atanp, sin-
     cosp, sinpi, cospi, tanpi, asinpi, acospi, atanpi,  atan2pi,
     sincospi - more trigonometric functions


SYNOPSIS

     cc [ flag ... ] file ...  -lsunmath -lm [ library ... ]

     #include <sunmath.h>

     void sincos(double x, double *s, double *c);

     double sind(double x);

     double cosd(double x);

     double tand(double x);

     double asind(double x);

     double acosd(double x);

     double atand(double x);

     double atan2d(double y, double x);

     void sincosd(double x, double *s, double *c);

     double sinpi(double x);

     double cospi(double x);

     double tanpi(double x);

     double asinpi(double x);

     double acospi(double x);

     double atanpi(double x);

     double atan2pi(double y, double x);

     void sincospi(double x, double *s, double *c);

     double sinp(double x);

     double cosp(double x);

     double tanp(double x);


     double asinp(double x);

     double acosp(double x);

     double atanp(double x);

     void sincosp(double x, double *s, double *c);


DESCRIPTION

     sincos(x,s,c) allows simultaneous computation of  *s:=sin(x)
     and *c:=cos(x).

     sind(x), cosd(x), and tand(x) return trigonometric functions
     of   degree   arguments.    sind(x):=   sin(x*pi/180).   The
     corresponding   inverse   functions    compute    asind(x):=
     asin(x)*180/pi.  Similarly atan2d(y,x):= atan2(y,x)*180/pi.

     sinpi(x),  cospi(x),  and  tanpi(x)  avoid   range-reduction
     issues because their definition sinpi(x):= sin(pi*x) permits
     range reduction that is  fast  and  exact  for  all  x.  The
     corresponding    inverse   functions   compute   asinpi(x):=
     asin(x)/pi.  Similarly atan2pi(y,x):= atan2(y,x)/pi.

     sinp(x), cosp(x), and tanp(x) use PI/2, the double precision
     approximation  to  pi/2,  in  the argument reduction step to
     reduce arguments exceeding PI/4 in magnitude  to  the  range
     -PI/4  to PI/4 . The argument reduction step is accomplished
     by the fmod function; thus it is much faster than using  the
     true  value  of  pi.   The  relation between sinp and sin is
     sinp(x):= sin(x*pi/PI).  The corresponding inverse functions
     asinp(x):=  asin(x)*PI/pi.   Since  PI/pi  is close to 1, we
     simply return asin(x).  The same  applies  to  acosp(x)  and
     atanp(x).


SEE ALSO

     asin(3M), acos(3M), atan(3M), atan2(3M),  cos(3M),  sin(3M),
     tan(3M).