import javafx.application.Application;
import javafx.scene.Group;
import javafx.scene.Scene;
import javafx.scene.canvas.Canvas;
import javafx.scene.canvas.GraphicsContext;
import javafx.stage.Stage;

public class Parabola extends Application {
    public void start(Stage stage) {
        stage.setTitle("������");

        final Canvas canvas = new Canvas(200, 200);
        GraphicsContext gc = canvas.getGraphicsContext2D();

        double a = -0.0025, b = 1, c = 0;
        for (int x0 = 0; x0 < 200; x0 += 10) {
            double y0 = a * x0 * x0 + b * x0 + c;
            int x1 = x0 + 10;
            double y1 = a * x1 * x1 + b * x1 + c;
            gc.strokeLine(x0, (int)y0, x1, (int)y1);
            System.out.printf("(%d, %.1f) -- (%d, %.1f)", x0, y0, x1, y1);
        }

        Group root = new Group();
        root.getChildren().addAll(canvas);
        Scene scene = new Scene(root);
        stage.setScene(scene);
        stage.show();
    }

    public static void main(String... args) {
        launch(args);
    }
}