mn

#include <iostream>
#define eps 0.000001
using namespace std;

double f(double t, double u)
{
    return 4 / (t * t) - u / t - u * u;
}
double df(double t, double u)
{
    return -1 / t - 2 * u;
}
double F(double t, double y, double x, double h)
{
    return x - y - (h / 2) * (f(t, y) + f(t + h, x));
}
double dF(double t, double x, double h)
{
    return 1 - (h / 2) * df(t + h, x);
}
void priblizhennoe(double t0, double U0, double h, int N)
{
    double y, t, x_prev, x_curr;
    y = U0;
    t = t0;
    bool a;
    cout << "При t" << 0 << " = " << t << " U" << 0 << " = " << y << "\n";
    for (int i = 0; i < N; i++)
    {
        x_curr = 0;
        x_prev = t;
        a = true;
        while (a)
        {
            x_curr = x_prev - F(t, y, x_prev, h) / dF(t, x_prev, h);
            if (abs(x_curr - x_prev) < eps)
                a = false;
            x_prev = x_curr;
        }
        t += h;
        y = x_curr;
        cout << "При t" << i + 1 << " = " << t << " U" << i + 1 << " = " << y << "\n";
    }
}
void tochnoe(int N, double h, double t0, double U0)
{
    double t, u;
    t = t0;
    u = U0;
    cout << "При t" << 0 << " = " << t << " U" << 0 << " = " << u << "\n";
    for (int i = 0; i < N; i++)
    {
        t = t + h;
        u = (2 * (t * t * t * t + 0.2)) / (t * (t * t * t * t - 1 / 5));
        cout << "При t" << i + 1 << " = " << t << " U" << i + 1 << " = " << u << "\n";
    }
}
int main()
{
    setlocale(LC_ALL, "RU");
    double t0, T, U0, h;
    int N;
    cout << "Введите t0 и T: \n";
    cin >> t0 >> T;
    cout << "Введите N и U0: \n";
    cin >> N >> U0;
    h = (T - t0) / N;
    cout << "Приближенные решения: \n";
    priblizhennoe(t0, U0, h, N);
    cout << "\n";
    cout << "Точные решения: \n";
    tochnoe(N, h, t0, U0);

    return 0;
}