To get the arccosine (in radians) of a number, use the Math.acos() method. This method returns the arccosine in radians of a number. The acos() method returns a numeric value between 0 and pi radians for x between -1 and 1. If the value of a number is outside this range, it returns NaN.
You can try to run the following code to get the arccosine (in radians) in JavaScript −
Example
<html> <head> <title>JavaScript Math acos() Method</title> </head> <body> <script> var value = Math.acos(-1); document.write("First Value : " + value ); var value = Math.acos(null); document.write("<br />Second Value : " + value ); var value = Math.acos(30); document.write("<br />Third Value : " + value ); var value = Math.acos("Demo Text"); document.write("<br />Fourth Value : " + value ); </script> </body> </html>
Output
First Value : 3.141592653589793 Second Value : 1.5707963267948966 Third Value : NaN Fourth Value : NaN