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 number is outside this range, it returns NaN.
Its syntax is as follows −
Math.acos( x ) ;
x − A number.
Returns the arccosine in radians of a number.
Try the following example program.
<html> <head> <title>JavaScript Math acos() Method</title> </head> <body> <script type="text/javascript"> var value = Math.acos(-1); document.write("First Test Value : " + value ); var value = Math.acos(null); document.write("<br />Second Test Value : " + value ); var value = Math.acos(30); document.write("<br />Third Test Value : " + value ); var value = Math.acos("string"); document.write("<br />Fourth Test Value : " + value ); </script> </body> </html>
First Test Value : 3.141592653589793 Second Test Value : 1.5707963267948966 Third Test Value : NaN Fourth Test Value : NaN