ActionScript: The Definitive Guide

Name

Math.acos( ) Method — compute the arc cosine of a number

Availability

Flash 5; may be used when exporting Flash 4 movies

Synopsis

Math.acos(x)

Arguments

x

A number between -1.0 and 1.0 (the cosine of an angle).

Returns

The angle, in radians, whose cosine is x. If x is not in the range -1.0 to 1.0, returns NaN.

Description

The arc cosine function (sometimes written as cos^-1) is the inverse of the cosine function. It returns the angle whose cosine has the specified value, in radians. The return value is in the range to π (i.e., to 3.14159...).

Example

trace (Math.acos(1.0));  // Displays: 0
trace (Math.acos(0.0));  // Displays: 1.5707... (i.e., pi/2)

See Also

Math.asin( ), Math.atan( ), Math.cos( )