C++ Math acos
This function computes the inverse cosine of a number in radian.
Syntax
Suppose a number is x. Syntax would be:
Example
float acos(float x);
double acos(double x);
long double acos(long double x);
double acos(integral x);
Note: If the value passed is an integer type, then it is cast to double.
Parameter
x : The value whose arc cosine is to be calculated. It should be in the range[-1,1].
Return value
| Parameter | Return value |
|---|---|
| -1≤x≤1 | (0,∏) |
| x<-1 or x>1 | Not a number |
Example 1
Let's see the simple example when the value of x is greater than 1.
Example
#include <iostream>
#include<math.h>
using namespace std;
int main()
{
float degree=90;
float x=degree*3.14/180;
std::cout << "Value of cosine is :" <<cos(x)<< std::endl;
cout<<"Inverse of cosine is :"<<acos(x);
return 0;
}
Output:
Output
Value of cosine is :0.000796274
Inverse of cosine is :nan
In this example, acos function calculates the inverse cosine of a number when the value of x is greater than 1.
Example 2
Let's see the simple example when the value of x is equal to zero.
Example
#include <iostream>
#include<math.h>
using namespace std;
int main()
{
float degree=0;
float x=degree*3.14/180;
std::cout << "Value of cosine is :" <<cos(x)<< std::endl;
cout<<"Inverse of cosine is :"<<acos(x);
return 0;
}
Output:
Output
Value of cosine is :1
Inverse of cosine is :1.5708
In this example, acos function calculates the inverse cosine of a number when the value of x is equal to zero.
Example 3
Let's see the simple example when the value x is less than -1.
Example
#include <iostream>
#include<math.h>
using namespace std;
int main()
{
float degree= -60;
float x=degree*3.14/180;
std::cout << "Value of cosine is :" <<cos(x)<< std::endl;
cout<<"Inverse of cosine is :"<<acos(x);
return 0;
}
Output:
Output
Value of cosine is :0.50046
Inverse of cosine is :nan
In this example, acos function calculates the inverse cosine of a number when the value of x is less than -1.