7 votes
Accepted

Why can't I use logic operator Or to specify multiple events with WhenEvent?

After reading these very helpful posts here and here, it seems to be better to use a function to inlude multiple events. This conclusion is definitely wrong. Please notice the posts you've found are ...
xzczd's user avatar
  • 65.4k
5 votes
Accepted

How to improve the following code to get rid of the warning messages?

\begin{align*} y^{\prime} & =f\left( x,y\right) \\ & =\frac{2xy}{y^{2}-1}\\ y\left( 2\right) & =1 \end{align*} We see at $y=1,x=2$ the $f\left( x,y\right) $ is not defined. Hence ...
Nasser's user avatar
  • 142k
4 votes
Accepted

How to determine for which initial conditions a system of ODE gives negative results?

How can I vary the initial conditions and see their effects on T solution? I mean make a Manipulate, something like this (the plot here is just T[t] and not the ...
Nasser's user avatar
  • 142k
3 votes

Help with plotting solution curves to the Gompertz equation

This is what I get. Note, your latex and code do not match. I assumed it is the Latex which is correct. But what I get does not exactly match what you show. So I think your ode is still missing ...
Nasser's user avatar
  • 142k
3 votes
Accepted

Is it possible to make a phase portrait of this system?

You have this system \begin{align*} x'(t)&=y(t)\\ y'(t)&=-(\omega_1^{2} x + \omega_2^{2} x^3) \csc(\alpha) \end{align*} Convert to state space. Let $x_1=...
Nasser's user avatar
  • 142k
2 votes

Failed to retrieve raw data from importing InterpolatingFunction derived from NDSolve

Export/import with ".m" files does not (it seems) preserve packed arrays. But InterpolatingFunction relies (it seems) on some of its data arrays being ...
Goofy's user avatar
  • 2,542
2 votes
Accepted

Failed to retrieve raw data from importing InterpolatingFunction derived from NDSolve

As we know file with extension .m is a plain text file, therefore all data in it are available to use. For example we generate file ...
Alex Trounev's user avatar
  • 43.3k
2 votes
Accepted

Help with plotting solution curves to the Gompertz equation

Maybe ...
cvgmt's user avatar
  • 68.9k
1 vote

How to determine for which initial conditions a system of ODE gives negative results?

There's a singularity when $T=0$, but it seems possible that $T'$ can stay finite. ...
Goofy's user avatar
  • 2,542

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