C++ acosh()

C++ acosh() returns arc (inverse) hyperbolic cosine of a number in radians.


The syntax of C++ acosh() is



xA double, float, or long double value. The value of x must lie in the range [1, infinity).


The return value depends on the type of value passed for parameter x.

The return value of acosh(x) is

  • double if x is double.
  • float if x is float.
  • long double if x is long double.

The synopsis of acosh() function is

double acosh(double x);
float acosh(float x);
long double acosh(long double x);
double acosh(T x); // For integral type

acosh() is a function of cmath library. Include cmath library at start of the program, if using acosh() function.


In this example, we read a number from user into variable x, and find its inverse hyperbolic cosine value using acosh().

C++ Program

#include <iostream>
using namespace std;

int main() {
    double x;
    cout << "Enter a number : ";
    cin >> x;
    double result = acosh(x);
    cout << "acosh(" << x << ") : " << result << " radians" << endl;


Enter a number : 1
acosh(1) : 0 radians
Program ended with exit code: 0
Enter a number : 25
acosh(25) : 3.91162 radians
Program ended with exit code: 0
Enter a number : 0
acosh(0) : nan radians
Program ended with exit code: 0


In this C++ Tutorial, we learned the syntax of C++ acosh(), and how to use this function to find the inverse hyperbolic cosine of given value, with the help of examples.