NAME

acos, acosf - arc cosine function

LIBRARY

Math Library (libm, -lm)

SYNOPSIS



double acos(double x)

float acosf(float x)

DESCRIPTION

The acos() and acosf() functions compute the principal value of the arc cosine of x in the range [0],.

RETURN VALUES

If |x|>1, acos(x) and acosf(x) set the global variable errno to EDOM.

SEE ALSO

asin(3), atan(3), atan2(3), cos(3), cosh(3), math(3), sin(3), sinh(3), tan(3), tanh(3)

STANDARDS

The acos() function conforms to ANSI X3.159-1989 (``ANSI C89'') .