I am trying to plot two functions in one plot (not working)

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Mahmoud Alshaghab 2020-11-25

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评论： Mahmoud Alshaghab 2020-11-28

I am trying to plot two functions in one graph and it not working for some reason. I tried to put dots for mutiplications and divisions but it is still not working. Some error appears and i can't fix it, please help

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Answer 1

Pier Giorgio Petrolini 2020-11-25

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Hello Mahmoud,

I can't see all your code, so I have to assume that all the rest is correct and, that you need to plot the functions "deltaP_AtoB1" and "deltaP_AtoB2" against the variable "V_c", correct ?! Try to rewrite the commands as follow:

Case 1) V_c = linspace(0,1,15)

deltaP_AtoB1 = ...

deltaP_AtoB2 = ...

plot(V_c, deltaP_AtoB1)

hold on

plot(V_c, deltaP_AtoB2)

hold off

===> in that case you need to use dots as you perfectly did because you're operating with vectors but you don't need to define deltaP_AtoB as symbolic variable, unless you need it after.

Case 2) Define V_c as a symbolic variable

deltaP_AtoB1 = ...

deltaP_AtoB2 = ...

fplot(V_c, deltaP_AtoB1)

hold on

fplot(V_c, deltaP_AtoB2)

hold off

xlim([0 15]) % eventually

==> in that case you don't need to use dots

I hope it helps, let me know if it works.

Kind regards,

PGP