ASIN(3)

NAME
1.5 `asin', `asinf'--arc sine

SYNOPSIS
     #include <math.h>
     double asin(double X);
     float asinf(float X);

DESCRIPTION
`asin' computes the inverse sine (arc sine) of the argument X. Arguments to `asin' must be in the range -1 to 1.
   `asinf' is identical to `asin', other than taking and returning floats.
   You can modify error handling for these routines using `matherr'.

RETURNS
`asin' returns values in radians, in the range of -pi/2 to pi/2. If X is not in the range -1 to 1, `asin' and `asinf' return NaN (not a number), set the global variable `errno' to `EDOM', and issue a `DOMAIN error' message.
   You can change this error treatment using `matherr'.

SEE ALSO
asin is part of the library. The full documentation for is maintained as a Texinfo manual. If info and are properly installed at your site, the command

    info

will give you access to the complete manual.