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

Table of contents


NAME

asinpif, asinpi, asinpil, asinpiw, asinpiq, asinpill, asinpidf, asinpid, asinpidl, asinpidll - arc sine function

SYNOPSIS

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

#include <mathcw.h>

extern float asinpif (float x);

extern double asinpi (double x);

extern long double asinpil (long double x);

extern __float80 asinpiw (__float80 x);

extern __float128 asinpiq (__float128 x);

extern long_long_double asinpill (long_long_double x);

extern decimal_float asinpidf (decimal_float x);

extern decimal_double asinpid (decimal_double x);

extern decimal_long_double asinpidl (decimal_long_double x);

extern decimal_long_long_double asinpidll (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 sine function, defined by asinpi(x) = asin(x) / pi.

The inverse function, sinpi(x) = sin(pi * x), avoids range-reduction issues because the argument x is always an exact scaling of pi.

The value of x should be in the range [-1,+1].


RETURN VALUES

For in-range arguments, the returned value is in the range [-pi/2, +pi/2]. 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

acospi(3CW), atan2pi(3CW), atanpi(3CW), cospi(3CW), cotanpi(3CW), sinpi(3CW), tanpi(3CW).