How to plot implicit ODE?
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How can I plot the solution of this ODE x^2.y’-y-y^2=0. Help me out please, I am new at Matlab.
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Davide Masiello
2022-9-27
编辑：Davide Masiello
2022-9-27
0 个投票
You need to solve it first.
The ODE can be easily made explicit
Then you can use any Matlab ODE solver (see this documentation) to numerically solve it and then plot it using the plot function.
I suggest you give it a go, and if you stumble into problems of any sort maybe come back here and we can fix them.
8 个评论
Juan Vicente
2022-9-27
I try to do it using ode45, but I am not getting the graph
First, add brackets to code the function correctly.
F = @(x,y) ((y^2+y)/x^2);
Second, the problem with you integration is that the first x value is 0.
Since x is at the denominator, this yields an array of NaN values
[x,y] = ode45(F,[0 5],0);
y
If you start x from 1, for instance, you do get a plot.
[x,y] = ode45(F,[1 5],0);
plot(x,y)
The plot is flat because the initial value for y is also zero, which make its derivative zero too, as you can see from the ODE.
Still for the sake of example, assume that y0 = 0.1.
[x,y] = ode45(F,[1 5],0.1);
plot(x,y)
Juan Vicente
2022-9-27
I get it now, but using the subjected approach, how can I plot the solution?
Davide Masiello
2022-9-27
I am not sure what you mean by that, could you please clarify?
Juan Vicente
2022-9-27
I got a homework to do for extra points and it is to plot the solution of that ode, I want to know if there is a way to plot it using Matlab? I attached the original graph
Davide Masiello
2022-9-27
Well, if you have an analytical solution then you can just use that for plotting.
But that's a different problem, so you should change your question.
Juan Vicente
2022-9-27
Torsten
2022-10-21
Solve the last equation for y and incorporate the boundary condition to get the constant C.
What's the problem ?
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