HTML and CSS Reference

In-Depth Information

Table 9.6
Math
Object Methods (continued)

Method

Functionality

Math.tan(Number)

Tangent of
Number
in radians

Math.toString(Number)

Converts
Number
to string

* Returns the value of
E
x
where
E
is Euler's constant and
x
is the argument passed to it. Euler's constant is

approximately 2.7183.

Square Root, Power of, and Pi.
The
Math
object comes with a number of common

mathematical constants (all uppercase), such as
PI
and natural log values, as well as meth-

ods to find the square root of a number, the power of a number, and so on. Example 9.20

demonstrates how to use some of these properties; the output is shown in Figure 9.24.

EXAMPLE
9.20

<html>

<head><title>The Math Object</title></head>

<body>

<h2>Math object Methods--sqrt(),pow()<br />

Math object Property--PI

</h2>

<h3>

<script type="text/javascript">

1

var num=16;

document.write("The square root of " +num+ " is ");

document.write(
Math.sqrt(num)
,".<br />");

2

document.write("PI is ");

3

document.write(
Math.PI
);

document.write(".<br />"+num+" raised to the 3rd power is " );

4

document.write(
Math.pow(num,3)
+ ".");

</script>

</h3>

</body>

</html>

EXPLANATION

1

The number 16 will be manipulated by
Math
methods and constants.

2

The
Math
object's
sqrt()
method returns the square root of number 16, which is 4.

3

The
Math
object's PI constant produces the value of PI.

4

The
Math
object's
pow()
methods raises and returns number 16 to the 3rd power,

which is 4096 (see Figure 9.24).