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Math Object

Last updated: June 20th, 2004

The Math object allows you to perform common math related tasks. Here are a few example uses:

var mygrade=Math.round(8.6) //returns 9
var mynum=Math.pow(2, 3) //returns 8

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Properties

Properties Description
E The constant of E, the base of natural logarithms.
LN2 The natural logarithm of 2.
LN10 The natural logarithm of 10.
LOG2E Base 2 logarithm of E.
LOG10E Base 10 logarithm of E.
PI Returns PI.
SQRT1_2 Square root of 1/2.
SQRT2 Square root of 2.

Methods

Methods Description
abs(x) Returns absolute value of x.
acos(x) Returns arc cosine of x in radians.
asin(x) Returns arc sine of x in radians.
atan(x) Returns arc tan of x in radians.
atan2(y, x) Counterclockwise angle between x axis and point (x,y).
ceil(x) Returns the smallest integer greater than or equal to x. (round up).
cos(x) Returns cosine of x, where x is in radians.
exp(x) Returns ex
floor(x) Returns the largest integer less than or equal to x. (round down)
log(x) Returns the natural logarithm (base E) of x.
max(a, b) Returns the larger of a and b.
min(a, b) Returns the lesser of a and b.
pow(x, y) Returns Xy
random() Returns a pseudorandom number between 0 and 1. Example(s).
round(x) Rounds x up or down to the nearest integer. It rounds .5 up. Example(s).
sin(x) Returns the Sin of x, where x is in radians.
sqrt(x) Returns the square root of x.
tan(x) Returns the Tan of x, where x is in radians.

Examples

random()

Math.random() //returns random number between 0 and 1, such as 0.634343434...
Math.floor(Math.random()*11) //returns random integer between 0 and 10

round(x)

Math.round(25.9) //returns 26
Math.round(25.2) //returns 25
Math.round(-2.58) //returns -3

var original=28.453
//round "original" to two decimals:
Math.round(original*100)/100 //returns 28.45


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