JavaScript Math.asin() Method

The JavaScript Math.asin() method accepts a number as a parameter and calculates the arcsine (inverse sine) of a number. The result is the angle (in radians) whose sine is the specified number.

If the argument provided to this method is in between -1 and 1 (inclusive), it returns the angle in radians between -PI/2 and PI/2. If the argument is outside the range of -1 or 1 or non-numeric, it returns "NaN (Not a Number)" as result.

Syntax

Following is the syntax of JavaScript Math.asin() method −

Math.asin(x);

Parameters

This method accepts only one parameter. The same is described below −

x: A numeric value between -1 and 1, representing the sine of an angle.

Return value

This method returns the arcsine (inverse sine) of the provided number in "radians".

Example 1

In this example, we're using the JavaScript Math.asin() method with values between -1 and 1 as arguments −

<html>
<body>
<script>
   let number1 = Math.asin(-1);
   document.write(number1, "<br>");

   let number2 = Math.asin(-0.5);
   document.write(number2, "<br>");

   let number3 = Math.asin(0);
   document.write(number3, "<br>");

   let number4 = Math.asin(0.5);
   document.write(number4, "<br>");

   let number5 = Math.asin(1);
   document.write(number5);
</script>
</body>
</html>

Output

It returns the arcsine of the provided arguments.

Example 2

Here, we are passing the out of range values as arguments to this method −

<html>
<body>
<script>
   let number1 = Math.asin(-2);
   document.write(number1, "<br>");

   let number2 = Math.asin(2);
   document.write(number2);
</script>
</body>
</html>

Output

We wil get "NaN" as result because both the arguments are not in range -1 to 1.

Example 3

Here, we are passing an argument which is not a numeric value −

<html>
<body>
<script>
   let string = "Tutorialspoint";
   let number = Math.asin("Tutorialspoint");

   document.write(number);
</script>
</body>
</html>

Output

If we execute the above program, it returns "NaN" as result.

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