[Matlab] Plotting two functions of the same variable against each other

[av8or]

I need to make two plots of volume as a function of time vs pressure as a function of time. When plotted the graph will have an enclosed area. I am having trouble on how to have MATLAB plot these two functions against each other.

My experience with MATLAB is having a function defined in a script file. I have not been exposed to using a function m file to define a function and reference it in a script.

My functions are as follows where (t) is the only variable, everything else is defined earlier in the file. I need to graph P vs Vc and P vs Ve. The order of magnitudes of Vc and Ve is different by 10^-3 hopefully that won't matter.

Vc =@(t) vc*sin(omega*t);
Ve =@(t) ve*cos(omega*t);
A =@(t) Vc(t)/(R*Tc) + vtl/(R*Ttl) + vr/(R*Tr) + Ve(t)/(R*Te);
P =@(t) M/A(t);

 

[Simon Bridge]

I need to make two plots of volume as a function of time vs pressure as a function of time. When plotted the graph will have an enclosed area. I am having trouble on how to have MATLAB plot these two functions against each other.

Why not just plot the vectors against each other?

 

[av8or]

Why not just plot the vectors against each other?

I actually had that idea shortly after posting this. Thank you for your response.

 

[Simon Bridge]

No worries - sometimes the process of asking a question will produce the answer.

 

[alphy]

Thank you for your question. To plot two functions of the same variable against each other in MATLAB, you can use the "plot" function. This function takes in two arrays, one for the x-values and one for the y-values, and plots them as a line graph. In your case, you can use the time values as the x-values and the output of your functions (P and Vc or Ve) as the y-values.

For example, to plot P vs Vc, you can use the following code:

t = linspace(0,10,100); % creates an array of 100 evenly spaced time values between 0 and 10
Vc_values = Vc(t); % calculates the Vc values at each time point
P_values = P(t); % calculates the P values at each time point
plot(Vc_values, P_values); % plots P vs Vc

You can do the same for P vs Ve by replacing Vc_values with Ve_values in the plot function.

If the order of magnitudes of Vc and Ve is different by 10^-3, it should not affect the plot as long as the values are within the range of the axes. If you find that the plot does not look right, you can adjust the axes limits using the "xlim" and "ylim" functions.

I hope this helps and let me know if you have any further questions. Good luck with your project!