JavaScript Math Object
The Math Object
The JavaScript Math object allows you to perform mathematical tasks.
The Math object is static.
All methods and properties can be used without creating a Math object first.
Math Properties (Constants)
The syntax for any Math property is :Math.property.
JavaScript provides 8 mathematical constants that can be accessed as Math properties:
Example
Math.PI // returns PI
Math.SQRT2 // returns the square root of 2
Math.SQRT1_2 // returns the square root of 1/2
Math.LN2 // returns the natural logarithm of 2
Math.LN10 // returns the natural logarithm of 10
Math.LOG2E // returns base 2 logarithm of E
Math.LOG10E // returns base 10 logarithm of E
Math Methods
The syntax for Math any methods is :Math.method(number)
Number to Integer
There are 4 common methods to round a number to an integer:
| Math.round(x) | Returns x rounded to its nearest integer |
| Math.ceil(x) | Returns x rounded up to its nearest integer |
| Math.floor(x) | Returns x rounded down to its nearest integer |
| Math.trunc(x) | Returns the integer part of x (new in ES6) |
Math.round()
Math.round(x) returns the nearest integer:
Examples
Math.ceil()
Math.ceil(x) returns the value of x roundedup to its nearest integer:
Example
Math.ceil(4.7);
Math.ceil(4.4);
Math.ceil(4.2);
Math.ceil(-4.2);
Math.floor()
Math.floor(x) returns the value of x roundeddown to its nearest integer:
Example
Math.floor(4.7);
Math.floor(4.4);
Math.floor(4.2);
Math.floor(-4.2);
Math.trunc()
Math.trunc(x) returns the integer part of x:
Example
Math.trunc(4.7);
Math.trunc(4.4);
Math.trunc(4.2);
Math.trunc(-4.2);
Math.sign()
Math.sign(x) returns if x is negative, null or positive.
- If x is positive it returns 1
- If x is negative it returns -1
- If x is zero, it returns 0
Note
Math.trunc() and Math.sign() were added toJavaScript 2015 - ES6.
Math.pow()
Math.pow(x, y) returns the value of x to the power of y:
Math.sqrt()
Math.sqrt(x) returns the square root of x:
Math.abs()
Math.abs(x) returns the absolute (positive) value of x:
Math.sin()
Math.sin(x) returns the sine (a value between -1 and 1) of the angle x (given in radians).
If you want to use degrees instead of radians, you have to convert degrees to radians:
Angle in radians = Angle in degrees x PI / 180.
Math.cos()
Math.cos(x) returns the cosine (a value between -1 and 1) of the angle x (given in radians).
If you want to use degrees instead of radians, you have to convert degrees to radians:
Angle in radians = Angle in degrees x PI / 180.
Math.min() and Math.max()
Math.min() andMath.max() can be used to find the lowest or highest value in a list of arguments:
Math.random()
Math.random() returns a random number between 0 (inclusive), and 1 (exclusive):
You will learn more aboutMath.random() in the next chapter of this tutorial.
The Math.log() Method
Math.log(x) returns the natural logarithm of x.
The natural logarithm returns the time needed to reach a certain level of growth:
Math.E and Math.log() are twins.
The Math.log2() Method
Math.log2(x) returns the base 2 logarithm of x.
The Math.log10() Method
Math.log10(x) returns the base 10 logarithm of x.
