How can I connect the points in the merged stem graph

Below is part of my code.

Do_FFT is a self-defined function for doing FFT.

    [P1,f_axis] = Do_FFT(file,fs,0);
    stem(f_axis,P1,'g');

    hold on;
    [Pf,f_axisf] = Do_FFT(file,fs,1,0.5);
    stem(f_axisf,Pf);

    [Pf,f_axisf] = Do_FFT(file,fs,1,0.5);
    stem(f_axisf,Pf,'r');

Just ignore title and legends of the image.

I'd like to know how to draw a line to connect all of the points. Thanks a lot.

Answer 1

[KSSV]

Use hold on and plot data.

figure
X = linspace(0,2*pi,50)';
Y = cos(X) ;
stem(X,Y)

hold on
plot(X,Y,'r')

[Wei-Min Chen]

Hi,

It seems like this approach only can connect the line from individual data. Now I have three stem graphics, their colors are 'r','g','b' respectively.

Can I connect them? Or I should plot them by using only one stem cmd, then plot(X,Y,'r') like you say?