# what is the difference between hold and plot of two curves in the same figure ?

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Commented: diadalina on 12 Dec 2017
i want to plot cos(x) and sin(x) in the same figure, i have two ways :
i can write for example :
X=0:pi,
Y=cos(X);
Z=sin(X);
Plot(X,Y,X,Z)
or the second way :
X=0:pi;
Y=cos(X);
Z=sin(Z);
Plot(X,Y)
Hold on
Plot(X,Z)
what is the difference between these two ways ?

Honglei Chen on 12 Dec 2017
If that's all you need, for the practical purpose, there isn't much difference. However, the internal settings in the two figures are different. For example, say you have another vector
W = cos(2*X);
and you want to plot it using
plot(X,W)
In the hold case, the new line will be added to the figure while in the other case, the axes will be cleared and the new plot contains only the new line.
HTH

thank Mr.Honglei for your answer, I did not understand correctly, look to what i had written :
figure(1)
x = 0 :0.1 :2*pi;
y1 = sin(x);
y2 = cos(x);
W = cos(2*x);
plot(x,W)
plot(x,y1,x,y2)
figure(2)
plot(x,y1)
hold on
plot(x,y2)
plot(x,W)
i can't see the difference ?
Honglei Chen on 12 Dec 2017
Isn't one of them has 3 curves and the other only 2?
no, they have 3 curves,i want to know the difference when i use plot and when i use hold on ?