NAME

trig_sun, sincos, sind, cosd, tand, asind, acosd, atand, atan2d, sincosd, sinp, cosp, tanp, asinp, acosp, atanp, sincosp, 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∗π/180). The corresponding inverse functions compute asind(x):= asin(x)∗180/π.  Similarly atan2d(y,x):= atan2(y,x)∗180/π. 

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

sinp(x), cosp(x), and tanp(x) use PI/2, the double precision approximation to π/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 π.  The relation between sinp and sin is sinp(x):= sin(x∗π/PI). The corresponding inverse functions asinp(x):= asin(x)∗PI/π. Since PI/π is close to 1, we simply return asin(x). The same applies to acosp(x) and atanp(x).

SEE ALSO

ieee_functions(3M), trig(3M). 

SunOS ProWorks_3.0.1  —  Last change: 1 Sep 1993