text: #include "SomeFunction.h"
  #define _USE_MATH_DEFINES
  #include <cmath>
  #include<iostream>
  #include<iomanip>  
  
  double SomeFunction::func(double x)
  {
      return 5 * cos(x) + 3;
  }
  
  double SomeFunction::integral(double x)
  {
      return 5 * sin(x) + 3 * x;
  }
  
  double SomeFunction::derivative(double x)
  {
      return -5 * sin(x);
  }
  
  double SomeFunction::sndDerivative(double x)
  {
      return -5 * cos(x);
  }
  
  double SomeFunction::fourthDerivative(double x)
  {
      return 5 * cos(x);
  }