C# | Math.Asin() Method

Last Updated : 31 Jan, 2019

Math.Asin() is an inbuilt Math class method which returns the angle whose sine value is given as a double value argument. If the argument is NaN, then the result will be NaN.

Syntax:

public static double Asin(double num)

Parameter:

num: It is the number that represents a sine and type of this parameter is System.Double. It must be greater than or equal to -1, but less than or equal to 1.

Return Type: Returns an angle Θ, measured in radians and its type is System.Double. Here the angle is always measured in radians, such that -π/2 ≤ Θ ≤ π/2.

Note: If the value of the num is greater than 1 or less than -1 or equals to NaN, then this method always returns NaN as result. To convert the radians(return value) to degrees multiply it by 180 / Math.PI. A positive return value always represents a counter clock-wise angle from the x-axis and a negative return value always represents a clockwise angle.

Examples:

Input  : Math.Asin(2)
Output : NaN

Input  : Math.Asin(0.3584)
Output : 0.366553473829125

Input  : Math.Asin(0.0)
Output : 0

Input  : Math.Asin(-0.0)
Output : 0

Input  : Math.Asin(Double.PositiveInfinity)
Output : NaN

Input  : Math.Asin(Double.NegativeInfinity)
Output : NaN

Program: To illustrate the Math.Asin() method

 // C# program to demonstrate working // of Math.Asin() method using System;    class Geeks {        // Main Method     public static void Main(String[] args)     {         double a = Math.PI;            // using Math.Asin() method         Console.WriteLine(Math.Asin(a));            // argument is greater than 1         Console.WriteLine(Math.Asin(2));                    Console.WriteLine(Math.Asin(0.3584));            double d = 0.0;         double e = -0.0;         double posi = Double.PositiveInfinity;         double nega = Double.NegativeInfinity;         double nan = Double.NaN;            // Input positive zero         // Output 0         double res = Math.Asin(d);            // converting to degree         // i.e. output is 0 degree         double rest = res * (180 / Math.PI);         Console.WriteLine(rest);            // Input negative zero         // Output 0         Console.WriteLine(Math.Asin(e));            // input PositiveInfinity         // Output NaN         Console.WriteLine(Math.Asin(posi));            // input NegativeInfinity         // Output NaN         Console.WriteLine(Math.Asin(nega));            // input NaN         // Output NaN         Console.WriteLine(Math.Asin(nan));     } }

Output:

NaN
NaN
0.366553473829125
0
0
NaN
NaN
NaN