ActionScript for Flash MX: The Definitive Guide, Second Edition

Math.acos() Method

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are reasonable approximations, but they are not necessarily identical to the native func-

tions supported in Flash 5 and later. The Flash 4 values are sufficiently accurate for “close-

enough” applications, such as graphics display, but are not accurate enough for critical

financial or engineering calculations.

Note that the trigonometric functions require angles to be measured in radians, whereas

Flash’s

MovieClip._rotation property is measured in degrees. There are 2π radians in a

circle (1 radian is approximately 57.3 degrees). To convert from radians to degrees, use the

formula:

degrees = (radians / Math.PI) * 180;

To convert from degrees to radians, use the formula:

radians = (degrees / 180) * Math.PI;

Flash automatically converts all Math object constants to literal numbers at compile-time.

See Also

“The Number Type” in Chapter 4

Math.abs() Method

compute the absolute value of a number

Flash 5; can be used when exporting Flash 4 movies

Math.abs(x)

Arguments

x Any integer or floating-point number.

Returns

The absolute value of x (a positive number of magnitude x).

Description

The abs( ) method calculates the distance between x and 0 (i.e., the absolute value of x). It

leaves zero and positive numbers unchanged and converts negative numbers ...