JavaScript Math Object
JavaScript Math Object
The JavaScript Math object allows you to perform mathematical tasks on numbers.
Math.PI; // returns 3.141592653589793
Math.round()
Math.round(x) returns the value of x rounded to its nearest integer:
TMuch Like Algebra
In programming, just like in algebra, we use variables (like price1) to hold values. In programming, just like in algebra, we use variables in expressions (total = price1 + price2). From the example below, you can calculate the total to be 11.
Math.round(4.7); // returns 5
Math.round(4.4); // returns 4
Math.pow()
Math.pow(x, y) returns the value of x to the power of y:
Math.pow(8, 2); // returns 64
Math.sqrt()
Math.sqrt(x) returns the square root of x:
Math.abs()
Math.abs(x) returns the absolute (positive) value of x:
Math.abs(-4.7); // returns 4.7
Math.ceil()
Math.ceil(x) returns the value of x rounded up to its nearest integer:
Math.ceil(4.4);
Math.floor()
Math.floor(x) returns the value of x rounded down to its nearest integer:
Math.floor(4.7); // returns 4
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.sin(90 * Math.PI / 180); // returns 1 (the sine of 90 degrees)
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.cos(0 * Math.PI / 180); // returns 1 (the cos of 0 degrees)
Math.min() and Math.max()
Math.min() and Math.max() can be used to find the lowest or highest value in a list of arguments:
Math.min(0, 150, 30, 20, -8, -200); // returns -200
Math.max(0, 150, 30, 20, -8, -200); // returns 150
Math.random()
Math.random() returns a random number between 0 (inclusive), and 1 (exclusive):
Math.random(); // returns a random number
Math Properties (Constants)
JavaScript provides 8 mathematical constants that can be accessed with the Math object
Math.E // returns Euler's number
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 Constructor
Unlike other global objects, the Math object has no constructor. Methods and properties are static. All methods and properties (constants) can be used without creating a Math object first.
var _lastName = "Johnson";
var _x = 2;
var _100 = 5;
