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JavaScript atan() and atan2() Methods

Definition and Usage

The atan() method returns the arctangent of a number as a numeric value between -PI/2 and PI/2 radians.
The atan2() method returns the angle theta of an (x,y) point as a numeric value between -PI and PI radians.

Syntax

Math.atan(x)
Math.atan2(x,y)

Parameter Description
x Required. A number
y Required. A number


Example 1 - atan()

The following example returns the arctangent of different numbers with the atan() method:

<script type="text/javascript">
document.write(Math.atan(0.50) + "<br />");
document.write(Math.atan(-0.50) + "<br />");
document.write(Math.atan(5) + "<br />");
document.write(Math.atan(10) + "<br />");
document.write(Math.atan(-5) + "<br />");
document.write(Math.atan(-10));
</script>

The output of the code above will be:

0.4636476090008061
-0.4636476090008061
1.373400766945016
1.4711276743037347
-1.373400766945016
-1.4711276743037347


Example 2 - atan2()

The following example returns the angle theta of different (x,y) points with the atan2() method:

<script type="text/javascript">
document.write(Math.atan2(0.50,0.50) + "<br />");
document.write(Math.atan2(-0.50,-0.50) + "<br />");
document.write(Math.atan2(5,5) + "<br />");
document.write(Math.atan2(10,20) + "<br />");
document.write(Math.atan2(-5,-5) + "<br />");
document.write(Math.atan2(-10,10));
</script>

The output of the code above will be:

0.7853981633974483
-2.356194490192345
0.7853981633974483
0.4636476090008061
-2.356194490192345
-0.7853981633974483 
JavaScript atan() and atan2() Methods Reviewed by 1000sourcecodes on 02:56 Rating: 5
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