Dive Into JavaScript

The JavaScript Math Object

The JavaScript Math object is a global object.

Math is not a constructor. Math is a static object, meaning that it's properties and methods are static and are accessible without an instance of the object.

For example, to get the absolute value of a number one needs to call the Math.abs() function. Creating an instance of the Math objects results in an error:

var my_math = new Math(); // wrong, throws an TypeError
Math.abs(-123); // 123

Likewise, you refer to the constant pi as Math.PI.

Math Object Properties

E

Mathematical constant e, the base of the natural logarithm, also known as Euler's number (2.718)

LN2

Natural logarithm of 2 (0.693)

LN10

Natural logarithm of 10 (2.302)

LOG2E

Base 2 logarithm of E (1.442)

LOG10E

Base 10 logarithm of E (0.434)

PI

Mathematical constant pi, the ratio of a circle's circumference to its diameter (3.141593)

SQRT1_2

Square root of 1 / 2, equivalent to 1 / Math.sqrt(2) (0.707)

SQRT2

Square root of 2, equivalent to Math.sqrt(2) (1.414)

Math Object Methods

abs(number)

Returns the absolute value of a number

acos(number)

Returns the arccosine of a number in radians. Complementary function of Math.cos()

asin(number)

Returns the arcsine of a number in radians

atan(number)

Returns the arctangent or a number in radians

atan2(y, x)

Returns the arctangent of the quotient of its arguments, similar to calculating the arctangent of y/x

ceil(number)

Returns the next smallest integer by rounding up the number if necessary

cos(number)

Returns the cosine of a number

exp(e)

Returns e (Math.E) raised to the power of x, equivalent to Math.pow(Math.E, x)

floor(number)

Returns the previous largest integer by rounding down the number if necessary

log(x)

Returns the natural logarithm of x

max([value1 [ , value2 [ , ...]]])

Returns the largest of zero or more values

min([value1 [ , value2 [ , ...]]])

Returns the smallest of zero or more values

pow(base, exponent)

Returns base raised to the power of exponent

random()

Generates a random value between 0 and 1

round(number)

Rounds a number to the nearest integer

sin(number)

Returns the sine of a number

sqrt(number)

Returns the square root of a number

tan(number)

Returns the tangent of a number