java.lang.StrictMath asin​(double a)


The asin​(double a) method of StrictMath class Returns the arc sine of a value; the returned angle is in the range -pi/2 through pi/2.

Special cases:

  • If the argument is NaN or its absolute value is greater than 1, then the result is NaN.
  • If the argument is zero, then the result is a zero with the same sign as the argument.


The asin​(double a) method of StrictMath class is static thus it should be accessed statically which means the we would be calling this method in this format:

StrictMath.asin​(double a)

Non static method is usually called by just declaring method_name(argument) however in this case since the method is static, it should be called by appending the class name as suffix. We will be encountering a compilation problem if we call the java compare method non statically.

Method Syntax

public static double asin​(double a)

Method Argument

Data Type Parameter Description
double a the value whose arc sine is to be returned.

Method Returns

The asin​(double a) method returns the arc sine of the argument.


Requires Java 1.3 and up

Java StrictMath asin​(double a) Example

Below is a java code demonstrates the use of asin​(double a) method of StrictMath class. Basically the program below ask for two user input, one for opposite and the other is hypotenuse. Our example program is design to calculate an angle given the user input. Take note of the usage of additional method that we have used which is toDegrees(). The method asin() returns an angle in radians which is not usually used thus we have used the toDegrees method to convert the result to degrees.


import java.util.Scanner;

 * A java example source code to demonstrate
 * the use of asin(double a)
 * method of StrictMath class

public class StrictMathAsinExample {

	public static void main(String[] args) {
		/* assume a right triangle
		 * Determine an angle
		 * given the opposite and hypotenuse 
		// Ask user input for the opposite
		System.out.print("Enter the opposite:");
		// declare the scanner object
		Scanner scan = new Scanner(;		
		// use scanner to get the user input and store it to a variable
		double opposite = scan.nextDouble();		
		// Ask another user input
		System.out.print("Enter the hypotenuse:");
		// store it to a variable
		double hypotenuse = scan.nextDouble();	
		// close the scanner object
		// get the result	
		double angleRadians = StrictMath.asin(opposite/hypotenuse);
		double angleDegrees = StrictMath.toDegrees(angleRadians);
		// print the result
		System.out.println("Angle of the triangle in radians: "+angleRadians);
		System.out.println("Angle of the triangle in degrees: "+angleDegrees);



Sample Output

Below is the sample output when you run the above example.

Java StrictMath asin(double a) method example output