## C# Math.Asin() – Examples

In this tutorial, we will learn about the C# Math.Asin() method, and learn how to use this method to find the arc sine of given double value, with the help of examples.

## Asin(Double)

Math.Asin(d) returns the angle whose sine is the specified number `d`. The angle returned shall be in radians.

If a value greater than 1 or less than -1 is given as argument, Acos() returns `Double.NaN`.

### Syntax

The syntax of Asin(d) method is

`Math.Asin(Double d)`

where

Return Value

The method returns value of type double.

### Example 1 – Math.Asin(0.5)

In this example, we will find the angle for which sine value is 0.5. We shall print the result both in radians and in degrees.

We know that sin(30 degrees) = 0.5. So, we should get the PI/6 radians as return value.

C# Program

```using System;

class Example {
static void Main(string[] args) {
Double d = 0.5;

Double angle = Math.Asin(d);
Console.WriteLine(\$"Angle in degrees : {(180 / Math.PI) * angle}");
}
}```

Output

```Angle in radians : 0.523598775598299
Angle in degrees : 30```

### Example 2 – Math.Asin(0)

In this example, we will find the angle for which sine value is 0.0. We know that sin(0 degrees) = 0. So, we should get the zero radians as return value.

C# Program

```using System;

class Example {
static void Main(string[] args) {
Double d = 0;

Double angle = Math.Asin(d);
Console.WriteLine(\$"Angle in degrees : {(180 / Math.PI) * angle}");
}
}```

Output

```Angle in radians : 0
Angle in degrees : 0```

### Example 3 – Asin(1.0)

In this example, we will find the angle for which sine value is 1.0. We know that sin(90 degrees) = 1.0. So, we should get the PI/2 radians as return value.

C# Program

```using System;

class Example {
static void Main(string[] args) {
Double d = 1.0;

Double angle = Math.Asin(d);
Console.WriteLine(\$"Angle in degrees : {(180 / Math.PI) * angle}");
}
}```

Output

```Angle in radians : 1.5707963267949
Angle in degrees : 90```

### Example 4 – Asin(5) – Invalid Argument

In this example, we will find the angle for which sine value is 5. We know that the range of sin(angle) is [-1.0, 1.0], and since the given argument is out of range, Asin() returns Double.NaN.

C# Program

```using System;

class Example {
static void Main(string[] args) {
Double d = 5;

Double angle = Math.Asin(d);
```Angle in radians : NaN