Java has a built-in `Math` class, defined in the `java.lang` package, which contains important functions to perform basic mathematical operations. The class has the **`asin()` method**, which is used to compute an $\arcsin$ or the $sin^{-1}$ (pronounced *inverse sin*) of the specified value.

> If $sin(\theta)$ is x then $sin^{-1}$(x) or $\arcsin(x)$ is $\theta$.

# Method definition
```java
public  static double asin(double value);
```
## Parameter
This function has one parameter, **`value`**, which represents the double value for which we have to find the $\arcsin$.

## Return value
The function returns the double value corresponding to the $\arcsin$ of the `value`. The returned value will lie within the range $\pi/2$ to $-\pi/2$. 

> Note: `Math.PI` is a constant equivalent to $\pi$ in mathematics.

If the value of `value` is infinity or #key# NaN :not a number #key#, then the returned value is `NaN`.

> Note: To convert an angle measured in radians to an equivalent angle measured in degrees and vice versa, we can use the built-in `Math.toDegrees(double angle_in_randians)` and `Math.toRadians(double angle_in_degrees)` methods.

# Code

class HelloWorld {
    public static void main( String args[] ) {
        double result = Math.asin(1);
        System.out.println("asin(1) = " + result);

        result = Math.asin(0);
        System.out.println("asin(0) = " +  result);

        result = Math.asin(0.48);
        System.out.println("asin(0.48) = " + result);

        result = Math.asin(0.66);
        System.out.println("asin(O.66) = " + result);

        result = Math.asin(0.8);
        System.out.println("asin(0.8) = " + result);

        result = Math.asin(1);
        System.out.println("asin(1) = " + result);

        result = Math.asin(Double.NaN);
        System.out.println("asin(NaN) = " + result);

        result = Math.asin(Double.POSITIVE_INFINITY);
        System.out.println("asin(∞) = " + result);
    }
}

What is Math.asin() in Java?

Java's Math.asin() computes the arcsin (inverse sin) of a value, returning results within -π/2 to π/2.