In this C++ tutorial, you will learn how to find the inverse cosine of a value using acos() function of cmath, with syntax and examples.
C++ acos()
C++ acos() returns inverse cosine of a number in radians.
Syntax
The syntax of C++ acos() is
acos(x)
where
Parameter | Description |
---|---|
x | A double, float, or long double. |
Returns
The return value depends on the type of value passed for parameter x. The return value of acos(x) is
- double if x is double.
- float if x is float.
- long double if x is long double.
The synopsis of acos() function is
double acos(double x); float acos(float x); long double acos(long double x); double acos(T x); // for integral type argument values
acos() is a function of cmath library. Include cmath library in the program, if using acos().
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Example
In this example, we read x value from the user and find the inverse cosine of this value using acos() function.
C++ Program
#include <iostream> #include<cmath> using namespace std; int main() { double x; cout << "Enter a value : "; cin >> x; double result = acos(x); cout << "acos(" << x << ") : " << result << " radians" << endl; }
Output
Enter a value : 0.5 acos(0.5) : 1.0472 radians Program ended with exit code: 0
Enter a value : 0 acos(0) : 1.5708 radians Program ended with exit code: 0
Conclusion
In this C++ Tutorial, we learned the syntax of C++ acos(), and how to use this function to find the inverse consine of a number, with the help of examples.