Math.Acos() is an inbuilt Math class method which returns the angle whose cosine is given as a double value argument. If the argument is NaN, then the result will be NaN.
Syntax:
Csharp
public static double Acos(double num)Parameter:
num: It is the number that represents cosine 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 0 ≤ Θ ≤ π. 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. Examples:
Input : Math.Acos(2)
Output : NaN
Input : Math.Acos(0.3584)
Output : 1.20424285296577
Input : Math.Acos(0.0)
Output : 1.5707963267949
Input : Math.Acos(-0.0)
Output : 1.5707963267949
Input : Math.Acos(Double.PositiveInfinity)
Output : NaN
Input : Math.Acos(Double.NegativeInfinity)
Output : NaN
Program: To illustrate the Math.Acos() method
// C# program to demonstrate working
// of Math.Acos() method
using System;
class Geeks {
// Main Method
public static void Main(String[] args)
{
double a = Math.PI;
// using Math.Acos() method
Console.WriteLine(Math.Acos(a));
// argument is greater than 1
Console.WriteLine(Math.Acos(2));
Console.WriteLine(Math.Acos(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 1.5707963267949
double res = Math.Acos(d);
// converting to degree
// i.e output will be 90 degree
double rest = res * (180 / Math.PI);
Console.WriteLine(rest);
// Input negative zero
// Output 1.5707963267949
Console.WriteLine(Math.Acos(e));
// input PositiveInfinity
// Output NaN
Console.WriteLine(Math.Acos(posi));
// input NegativeInfinity
// Output NaN
Console.WriteLine(Math.Acos(nega));
// input NaN
// Output NaN
Console.WriteLine(Math.Acos(nan));
}
}
Output:
Reference: https://learn.microsoft.com/en-us/dotnet/api/system.math.acos?redirectedfrom=MSDN#System_Math_Acos_System_Double_NaN NaN 1.20424285296577 90 1.5707963267949 NaN NaN NaN
