function anima_Newton_Raphson(f, df, a0)
    clc

    %%% Creamos un vector x

    x0 = a0


    for k = 1:10

        x1 = x0 - f(x0)/df(x0);
        if x1 > x0 
            x = (x0-1):0.1:(x1+1);
        else
            x = (x1-1):0.1:(x0+1);
        end;
        y = f(x);
        close all

        fig = figure();
        set(fig, 'color', 'white')
        plot(x,y, 'LineWidth', 2)
        grid on
        xlabel('x')
        ylabel('y')
        hold on;
        
        yc = df(x0)*(x1-x0) + f(x0);
        
        if yc > f(x1)
            yb = f(x1):0.01:yc;
        else
            yb = yc:0.01:f(x1);
        end;
        
        xb = ones(length(yb))*x1;

        plot(xb,yb, 'r-', 'LineWidth', 2);

        
        yc = df(x0)*(x-x0) + f(x0);

        plot(x, yc, 'g-', 'LineWidth', 2);
        

        if abs(f(x1)) > 1e-6
            x0 = x1
        else
            break;
        end;                     

        input('Preciona una tecla para continuar ');
    end;
end