JavaScript: The Definitive Guide, 5th Edition

Name

Math: mathematical functions and constants — ECMAScript v1

Synopsis

Math.constantMath.function( )

Constants

Math.E

The constant e, the base of the natural logarithm.

Math.LN10

The natural logarithm of 10.

Math.LN2

The natural logarithm of 2.

Math.LOG10E

The base-10 logarithm of e.

Math.LOG2E

The base-2 logarithm of e.

Math.PI

The constant π.

Math.SQRT1_2

The number 1 divided by the square root of 2.

Math.SQRT2

The square root of 2.

Static Functions

Math.abs( )

Computes an absolute value.

Math.acos( )

Computes an arccosine.

Math.asin( )

Computes an arcsine.

Math.atan( )

Computes an arctangent.

Math.atan2( )

Computes the angle from the X axis to a point.

Math.ceil( )

Rounds a number up.

Math.cos( )

Computes a cosine.

Math.exp( )

Computes a power of e.

Math.floor( )

Rounds a number down.

Math.log( )

Computes a natural logarithm.

Math.max( )

Returns the larger of two numbers.

Math.min( )

Returns the smaller of two numbers.

Math.pow( )

Computes x ^y

Math.random( )

Computes a random number.

Math.round( )

Rounds to the nearest integer.

Math.sin( )

Computes a sine.

Math.sqrt( )

Computes a square root.

Math.tan( )

Computes a tangent.

Description

Math is an object that defines properties that refer to useful mathematical functions and constants. These functions and constants are invoked with syntax like this:

y = Math.sin(x);
area = radius * radius * Math.PI;

Math is not a class of objects as Date and String are. There is no Math( ) constructor, and functions like Math.sin( ) are simply functions, ...