double sinh(double);

return the hyperbolic sinus

#include <iostream> /* including standard library */
#include <cmath> /* including math library */
 
using namespace std;
int main (void)
{
  double x;
  x = log(4.2);
 
  //cout.setf(ios::fixed, ios::floatfield);
  cout.precision(8);
 
  cout << "hyperbolic sine of " << x << " is " << sinh(x) << endl;
  return 0;
}

  hyperbolic sine of 1.4350845 is 1.9809524