Manpage of ACOS

ACOS

Section: NEWLIB (3)
Updated: 2005 Feb 23
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NAME

1.2 `acos', `acosf'--arc cosine

SYNOPSIS

     #include <math.h>
     double acos(double X);
     float acosf(float X);

DESCRIPTION

`acos' computes the inverse cosine (arc cosine) of the input value. Arguments to `acos' must be in the range -1 to 1.

`acosf' is identical to `acos', except that it performs its calculations on `floats'.

RETURNS

`acos' and `acosf' return values in radians, in the range of 0 to pi.

If X is not between -1 and 1, the returned value is NaN (not a number) the global variable `errno' is set to `EDOM', and a `DOMAIN error' message is sent as standard error output.

You can modify error handling for these functions using `matherr'.