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The JavaScript Math object allows you to perform various calculations using
its member functions. This two-part tutorial takes you through the use of the Math
object, and then how to use the Math.random() function to get random numbers.
The Math object of JavaScript allows you to perform certain calculations by using method functions of the Math object. Also, it
provides a few constants such as pi. The easiest way to get a value is to define a variable and set its value to a property or
function of the Math Object.
If you want to use a property, which returns a constant value (such as pi), you would write something like this:
var my_car=Math.property;
You would replace the word "property" with the property you want to use.
So, if you want to use the value of pi in a variable, you would use the PI property of the Math
object. You would write:
var my_pie=Math.PI;
This returns the pi constant, a number with lots of decimals, or 3.14.....
If you want to use a member function, which performs a calculation, you would write something like this:
var my_house=Math.function(x);
Most of the member functions have one or more parameters, which is what
the "x" is for. You can replace x with a number or variable. You would
replace the word "function" with the function you want to use. For
instance, if you want the square root of a number, you can call the
square root member function of the Math object with the number as the
parameter:
var my_money=Math.sqrt(2);
This gives back the square root of 2, which is another number with lots of decimals, around 1.41.....
Now that you have seen how little money I have, be sure to take notice that the "M" in Math is always capitalized. The
word Math is followed by the dot operator (.), and then the property or member function you want to use.
These are not too difficult to use now that you know how to get to them. Here are some of the properties you can use, these
return the constant values:
| Math.PI |
Returns the constant pi |
| Math.SQRT2 |
Returns the square root of 2 |
| Math.SQRT1_2 |
Returns the square root of 1/2 |
Below is a table of some of the commonly used member functions of the Math object. These functions calculate
values based on the parameters you send to them (except the random function):
| Method Function |
What it Does |
| abs(x) |
Returns the absolute value of the variable x. |
| cos(x) |
Returns the cosine of the variable x. |
| log(x) |
Returns the natural log of the variable x. |
| max(x,z) |
Returns the larger of the two variables x and z. |
| min(x,z) |
Returns the smaller of the two variables x and z. |
| pow(x,z) |
Returns the value of the variable x to the zth power. |
| random() |
Returns a random number between 0 and 1. |
| round(x) |
Returns the variable x rounded to the nearest integer. |
| sin(x) |
Returns the sine of the variable x. |
| sqrt(x) |
Returns the square root of the variable x. |
| tan(x) |
Returns the tangent of the variable x. |
Hopefully, you will find some of these useful in your scripts. We may start using some of these in
future tutorials, so be on the lookout!
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Tutorials 
