ActionScript for Flash MX: The Definitive Guide, 2nd Edition By Colin Moock
Chapter 18. ActionScript Language Reference
Math.sin( ) Method
Flash 5; can be used when exporting Flash 4 movies
compute the sine of an angle
Math.sin(theta)
Arguments
theta
An angle, in radians (not degrees), normally in the range of 0 to 2, although any angle will suffice, as sine is a periodic function.
Returns
The sine of theta (the result is in the range of -1.0 to 1.0).
Description
The sin( ) method returns the trigonometric sine of an angle. In a right triangle, the sine of an angle is the result of dividing the length of the side opposite the angle by the triangle's hypotenuse.
Usage
Note that sin( ) expects angles to be provided in radians, not degrees.