15.5.2 acos

acos(x)

Returns the arc cosine of numerical x, in radians. This function accepts complex arguments.

For ordinary (real) arguments, the arc cosine is only defined for arguments between -1 and +1 (inclusive). Multiply by #rad to get degrees.

The arc cosine function is defined for any complex argument.

Reverse: cos

See also: asin, atan, #rad, Trigonometry, Complex Functions