Flash CS3 Documentation

ActionScript 2.0 Language Reference > ActionScript classes > Math > cos (Math.cos method)

cos (Math.cos method)

Computes and returns the cosine of the specified angle in radians. To calculate a radian, see the description of the Math class entry.

Availability: ActionScript 1.0; Flash Player 5 - In Flash Player 4, the methods and properties of the Math class are emulated using approximations and might not be as accurate as the non-emulated math functions that Flash Player 5 supports.

Parameters

x:Number - A number that represents an angle measured in radians.

Returns

Number - A number from -1.0 to 1.0.

Example

The following example displays the cosine for several different angles.

trace (Math.cos(0)); // 0 degree angle. Output: 1
trace (Math.cos(Math.PI/2)); // 90 degree angle. Output: 6.12303176911189e-17
trace (Math.cos(Math.PI)); // 180 degree angle. Output: -1
trace (Math.cos(Math.PI*2)); // 360 degree angle. Output: 1

Note: The cosine of a 90 degree angle is zero, but because of the inherent inaccuracy of decimal calculations using binary numbers, Flash Player will report a number extremely close to, but not exactly equal to, zero.

See also

acos (Math.acos method), asin (Math.asin method), atan (Math.atan method), atan2 (Math.atan2 method), sin (Math.sin method), tan (Math.tan method)

Flash CS3