Wednesday, December 25, 2013

Math



Math is a built-in object that has properties and methods for mathematical constants and functions.
All properties and methods of Math are static. 
You refer to the constant pi as Math.PI and you call the sine function as Math.sin(x), where x is the method's argument.

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

Properties

Properties
Description
E
The constant of E, the base of natural logarithms.
alert(Math.E); // 2.718281828459045
LN2
The natural logarithm of 2.
alert(Math.LN2); // 0.6931471805599453
LN10
The natural logarithm of 10.
alert(Math.LN10); // 2.302585092994046
LOG2E
Base 2 logarithm of E.
alert(Math.LOG2E);//1.4426950408889634
LOG10E
Base 10 logarithm of E.
alert(Math.LOG10E);// 0.4342944819032518
PI
Returns PI.
alert(Math.PI);// 3.141592653589793
SQRT1_2
Square root of 1/2.
alert(Math.SQRT1_2);//0.7071067811865476
SQRT2
Square root of 2.
alert(Math.SQRT2);//1.4142135623730951

Methods

Methods
Description
abs(x)
Returns absolute value of x.
Example:
Math.abs('-1');     // 1
Math.abs(-2);       // 2
Math.abs(null);     // 0
Math.abs("string"); // NaN
Math.abs();         // NaN
Math.abs(‘1.234’);  //1.234 
Math.abs('-1.56')   //1.56
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)
Counter clockwise angle between x axis and point (x,y).
ceil(x)
Returns the smallest integer greater than or equal to x. (round up).
Example:
alert(Math.ceil(7.0004));//8
alert(Math.ceil(7));//7

alert(Math.ceil(-7.01));//-7
alert(Math.ceil(-7.99));//-7
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)
Example:
alert(Math.floor(7.0004));//8
alert(Math.floor(7.99));//7

alert(Math.floor(-7.01));//-8
alert(Math.floor(-7.99));//-8
log(x)
Returns the natural logarithm (base E) of x.
max(a, b)
Returns the larger of a and b.
Example:
alert(Math.max(12,12));//12
alert(Math.max(12,21));//21
min(a, b)
Returns the lesser of a and b.
Example:
alert(Math.min(12,12));//12
alert(Math.min(12,21));//12
pow(x, y)
Returns Xy
random()
Returns a pseudorandom number between 0 and 1.
Example:
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)
Rounds x up or down to the nearest integer. It rounds .5 up.
Example:
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
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.