int 5

#include "pch.h"
#include <iostream>
#include <iomanip>
#include <math.h>
using namespace std;

double func(double x) {
	return sqrt(x) - pow(cos(x), 2);
}

double Gaus(double a, double b, int n) {
	double h = (b - a) / n;
	double x0 = a + h / 2.;
	double x1 = x0 - (h / 2.)*0.7745966692;
	double x2 = x0 + (h / 2.)*0.7745966692;
	long double ans = 0;
	for (int i = 0; i < n; i++) {
		ans += (5 * func(x1) + 8 * func(x0) + 5 * func(x2));
		x0 += h;
		x1 = x0 - (h / 2.)*0.7745966692;
		x2 = x0 + (h / 2.)*0.7745966692;
	}
	return ans*h/18.;
}
int main(void)
{
	setlocale(LC_ALL, "Russian");
	cout << "a=";
	double a;
	cin >> a;
	cout << "b=";
	double b;
	cin >> b;
	int m = 3;
	double x[20];
	double y[20];
	double h = (b - a) / 10.;
	int k = (b - a) / h;
	for (int i = 0; i <= k + 1; i++)
	{
		x[i] = a + i * h;
		y[i] = func(x[i]);
	}
	double dy[20];
	dy[0] = (4 * y[1] - y[2] - 3 * y[0]) / (2 * h);
	dy[k] = (4 * y[k - 1] - y[k - 2] - 3 * y[k]) / (2 * h);
	for (int i = 1; i < k; i++) dy[i] = (y[i + 1] - y[i - 1]) / (2 * h);
	double Dy[20];
	for (int i = 0; i <= k; i++)Dy[i] = 2 * x[i] - 5 * sin(x[i]);
	double d2y[20];
	d2y[0] = (y[0] - 2 * y[1] + y[2]) / pow(h, 2);
	d2y[k] = (y[k-2] - 2 * y[k-1] + y[k]) / pow(h, 2);
	for (int i = 1; i < k; i++)d2y[i] = (y[i - 1] - 2 * y[i] + y[i + 1]);
	double D2y[20];
	for (int i = 0; i <= k; i++)D2y[i] = 2 - 5 * cos(x[i]);
	cout << setw(5) << "X" << setw(10) << "Y" << setw(10) << "dY" << setw(10) << "DY" << setw(10) << "d2Y" << setw(10) << "D2Y" << endl;
	for(int i = 0;i<=k;i++)
	cout << setw(5) << x[i] << setw(10) << y[i] << setw(10) << dy[i] << setw(10) << Dy[i] << setw(10) << d2y[i] << setw(10) << D2y[i] << endl;
	cout << Gaus(a, b, m);
	return 0;
}