#include <iostream>
#include <iomanip>
using namespace std;
int main() {
    double a, b, h, y;
    double eps = 1e-12;
    cin >> a >> b >> h;
    for (double i = a; i < b + eps; i += h) {
        cout << fixed << setprecision(6) << i << '\t';
        if (abs(abs(i) - 1) < eps) cout << "undefined" << endl;
        else cout << fixed << setprecision(6) << 1 / (i * i - 1) << endl;
    }
    return 0;
}




/*
struct point {
	int x, y, z;
};
int perimetr(point a, point b, point c) {
	double ot1, ot2, ot3, p;
	ot1 = sqrt((a.x - b.x) * (a.x - b.x) + (a.y - b.y) * (a.y - b.y) + (a.z - b.z) * (a.z - b.z));
	ot2 = sqrt((b.x - c.x) * (b.x - c.x) + (b.y - c.y) * (b.y - c.y) + (b.z - c.z) * (b.z - c.z));
	ot3 = sqrt((a.x - c.x) * (a.x - c.x) + (a.y - c.y) * (a.y - c.y) + (a.z - c.z) * (a.z - c.z));
	p = ot1 + ot2 + ot3;
	return p;
}
int main() {
	int n, p;
	double m_p = 1e9;
	setlocale(LC_ALL, "Russian");
	cout << "Количество точек >> ";
	cin >> n;
	vector <point> toch;
	for (int i = 0; i < n; i++) {
		cout << "Введите координаты точки\n x = ";
		cin >> toch[i].x; // здесь ошибка
		cout << "y = ";
		cin >> toch[i].y;
		cout << "z = ";
		cin >> toch[i].z;
	}
	for (int i = 0; i < n - 2; i++) {
		for (int j = i + 1; i < n - 1; i++) {
			for (int k = j + 1; k < n; k++) {
				p = perimetr(toch[i], toch[j], toch[k]);
				if (m_p < p) m_p = p;
			}
		}
	}
	cout << m_p;
}*/