Core JavaScript 1.5 Guide:Predefined Core Objects:Math Object

From MDC

[edit] Math Object

The predefined Math object has properties and methods for mathematical constants and functions. For example, the Math object's PI property has the value of pi (3.141...), which you would use in an application as

Math.PI

Similarly, standard mathematical functions are methods of Math. These include trigonometric, logarithmic, exponential, and other functions. For example, if you want to use the trigonometric function sine, you would write

Math.sin(1.56)

Note that all trigonometric methods of Math take arguments in radians.

The following table summarizes the Math object's methods.

Method	Description
abs	Absolute value
sin, cos, tan	Standard trigonometric functions; argument in radians
acos, asin, atan, atan2	Inverse trigonometric functions; return values in radians
exp, log	Exponential and natural logarithm, base e
ceil	Returns least integer greater than or equal to argument
floor	Returns greatest integer less than or equal to argument
min, max	Returns greater or lesser (respectively) of two arguments
pow	Exponential; first argument is base, second is exponent
random	Returns a random number between 0 and 1.
round	Rounds argument to nearest integer
sqrt	Square root

Table 7.1: Methods of Math

Unlike many other objects, you never create a Math object of your own. You always use the predefined Math object.