ATANP 3CW "21 March 2008" "mathcw-1.00"

Table of contents


NAME

atanpf, atanp, atanpl, atanpw, atanpq, atanpll, atanpdf, atanpd, atanpdl, atanpdll - arc tangent function

SYNOPSIS

cc [ flags ] -I/usr/local/include file(s) -L/usr/local/lib -lmcw [ ... ]

#include <mathcw.h>

extern float atanpf (float x);

extern double atanp (double x);

extern long double atanpl (long double x);

extern __float80 atanpw (__float80 x);

extern __float128 atanpq (__float128 x);

extern long_long_double atanpll (long_long_double x);

extern decimal_float atanpdf (decimal_float x);

extern decimal_double atanpd (decimal_double x);

extern decimal_long_double atanpdl (decimal_long_double x);

extern decimal_long_long_double atanpdll (decimal_long_long_double x);

NB: Functions with prototypes containing underscores in type names may be available only with certain extended compilers.


DESCRIPTION

Compute the principal value of the arc tangent function, defined by atanp(x) = atan(x) * fl(pi)/pi. The scale factor is essentially one, so this function just computes atan(x).

The value of x should be in the range [-Infinity,+Infinity], for which the function range is [-pi/2,+pi/2].


RETURN VALUES

For in-range arguments, the returned value is in the range [+0,+pi]. Otherwise, the returned value is a quiet NaN.

ERRORS

For out-of-range, Infinity and NaN arguments, the returned value is a quiet NaN, and errno is set to EDOM.

SEE ALSO

acosp(3CW), asinp(3CW), atan2p(3CW), cosp(3CW), cotanp(3CW), sinp(3CW), tanp(3CW).