error: can not find a symbol Java

I have a problem.

I want to recover panel2 of this program to open it in another one by:

public JPanel getPanel2()
{
    return panel2;
}

To display that panel2 in the other program I have this:

if(e.getSource()== miCalcu)
            {
                panel.setVisible(false);
                panel= calcul.getPanel2();
                panel.setVisible(true);
                add(panel);
                setVisible(true);

            }

But I need that getPanel2 that does not recognize me.

I get the error mentioned above. I have used this same function for other programs and open these, in another click on a JMenuItem , the rest, work perfectly with that instruction, I recover the panel2 without problem and with the same instruction. But this brought me this error. Here a fragment of the code (436 lines in total). If necessary, I write everything.

import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JButton;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JTextArea;

import java.awt.GridLayout;
import java.awt.FlowLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.event.WindowEvent;
import java.awt.Panel;

public class Calculadora extends JFrame implements ActionListener
{
    private JTextField tfNumero = new JTextField(8);

    private JButton bSuma, bResta, bMultiplica, bDivide, bIgual, bClear, bPunto;
    private JButton b0, b1, b2, b3, b4, b5, b6, b7, b8, b9;
    private JButton bFactorial, bExpo, bRaiz, bCuadrado;
    private Panel panel1, panel2;

    private float n1, n2;
    private String operacion = "";
    private String strNumero = "";
    private int base;
    int sum,c;
    int x;
    String resSuma,resRes,resMul,resDiv,resExpo;

    public Calculadora()
    {
        super("Calculadora");

        panel1 = new Panel();
        panel2 = new Panel();
        panel1.setLayout(new GridLayout(1,2));
        panel2.setLayout(new GridLayout(5,4));


        panel1.add(tfNumero);

        bClear = new JButton("clear");
        panel1.add(bClear);     


        b7 = new JButton("7");
        panel2.add(b7);

        b8 = new JButton("8");
        panel2.add(b8);

        b9 = new JButton("9");
        panel2.add(b9);

        bSuma = new JButton("+");
        panel2.add(bSuma);

        b4 = new JButton("4");
        panel2.add(b4);

        b5 = new JButton("5");
        panel2.add(b5);

        b6 = new JButton("6");
        panel2.add(b6);

        bResta = new JButton("-");
        panel2.add(bResta);

        b1 = new JButton("1");
        panel2.add(b1);

        b2 = new JButton("2");
        panel2.add(b2);

        b3 = new JButton("3");
        panel2.add(b3);

        bMultiplica = new JButton("x");
        panel2.add(bMultiplica);

        b0 = new JButton("0");
        panel2.add(b0);

        bPunto = new JButton(".");
        panel2.add(bPunto);

        bIgual = new JButton("=");
        panel2.add(bIgual);

        bDivide = new JButton("/");
        panel2.add(bDivide);

        bFactorial = new JButton("x!");
        panel2.add(bFactorial);

        bRaiz = new JButton("sqrt(x)");
        panel2.add(bRaiz);

        bCuadrado = new JButton("x^2");
        panel2.add(bCuadrado);

        bExpo = new JButton("y^x");
        panel2.add(bExpo);


        b0.addActionListener(this);
        b1.addActionListener(this);
        b2.addActionListener(this);
        b3.addActionListener(this);
        b4.addActionListener(this);
        b5.addActionListener(this);
        b6.addActionListener(this);
        b7.addActionListener(this);
        b8.addActionListener(this);
        b9.addActionListener(this);
        bClear.addActionListener(this);
        bSuma.addActionListener(this);
        bResta.addActionListener(this);
        bMultiplica.addActionListener(this);
        bDivide.addActionListener(this);
        bIgual.addActionListener(this);
        bPunto.addActionListener(this);
        bFactorial.addActionListener(this);
        bExpo.addActionListener(this);
        bRaiz.addActionListener(this);
        bCuadrado.addActionListener(this);


        setLayout(new FlowLayout());
        add(panel1);
        add(panel2);
        setSize(350,220);
        setVisible(true);
    }

    public JPanel getPanel2()
            {
                return panel2;
            }