include iostream include cmath using namespace std double double retur

#include <iostream>
#include <cmath>

using namespace std;

double f(double x) {
    return pow(x, 2);
}

double interpolate(double x, double x1, double x2) {
    return f(x1) + (f(x2) - f(x1)) * (x - x1) / (x2 - x1);
}

int main() {
    double x1, x2, x;
    cout << "Enter x1:" << endl;
    cin >> x1;
    cout << "Enter x2:" << endl;
    cin >> x2;
    cout << "Enter x between x1 and x2:" << endl;
    cin >> x;
    cout << "f(x) = " << interpolate(x, x1, x2) << endl;
    return 0;
}