NAME

trig, sin, cos, tan, asin, acos, atan, atan2 − trigonometric functions

SYNOPSIS

#include <math.h>

double sin(double x);

double cos(double x);

double tan(double x);

double asin(double x);

double acos(double x);

double atan(double x);

double atan2(double y, double x);

DESCRIPTION

sin(x), cos(x) and tan(x) return trigonometric functions of radian arguments.  Trigonometric argument reduction is discussed in the

asin(x) returns the arc sine of x in the range −π/2 to π/2. 

acos(x) returns the arc cosine of x in the range 0 to π. 

atan(x) returns the arc tangent of x in the range −π/2 to π/2. 

atan2(y,x) and hypot(x,y) (see hypot(3M)) convert rectangular coordinates (x,y) to polar (r,θ); atan2(y,x) computes θ, the argument or phase, by computing an arc tangent of y/x in the range −π to π.  atan2(0.0,0.0) is 0.0, in conformance with SVID. 

DIAGNOSTICS

These functions handle exceptional arguments in the spirit of ANSI/IEEE Std 754-1985 and in conformance with SVID.  sin(±∞), cos(±∞) and tan(±∞) return NaN; asin(x) or acos(x) with |x|>1, return 0.0. In addition, asin(x), acos(x), and atan2(y,x) may also set errno and call matherr(3M). 

SEE ALSO

hypot(3M), matherr(3M)

SunOS 5.1  —  Last change: 30 Apr 1992