.\"	@(#)sin.3m	6.1 (Berkeley) 5/15/85
.\"
.TH SIN 3M  "May 15, 1985"
.AT 3
.SH NAME
sin, cos, tan, asin, acos, atan, atan2 \- trigonometric functions
.SH SYNOPSIS
.nf
.B #include <math.h>
.PP
.B double sin(x)
.B double x;
.PP
.B double cos(x)
.B double x;
.PP
.B double asin(x)
.B double x;
.PP
.B double acos(x)
.B double x;
.PP
.B double atan(x)
.B double x;
.PP
.B double atan2(x, y)
.B double x, y;
.fi
.SH DESCRIPTION
.I Sin, cos
and
.I tan
return trigonometric functions of radian arguments.
The magnitude of the argument should be checked
by the caller to make sure the result is meaningful.
.PP
.I Asin
returns the arc sin in the range \-\(*p/2 to \(*p/2.
.PP
.I Acos
returns the arc cosine in the range 0 to \(*p.
.PP
.I Atan
returns the arc tangent of
.I x
in the range \-\(*p/2 to \(*p/2.
.PP
.I Atan2
returns the arc tangent of
.I x/y
in the range \-\(*p to \(*p.
.SH DIAGNOSTICS
Arguments of magnitude greater than 1 cause
.I asin
and
.I acos
to return value 0;
.I errno
is set to EDOM.  The value of
.I tan
at its singular points is a huge number, and
.I errno
is set to ERANGE.
.SH BUGS
The value of
.I tan
for arguments greater than about 2**31 is garbage.