Linked Questions

27
votes
6answers
47k views

How can I plot the direction field for a differential equation?

I'd like to plot the graph of the direction field for a differential equation, to get a feel for it. I'm a novice, right now, when it comes to plotting in Mathematica, so I'm hoping that someone can ...
37
votes
3answers
52k views

Plotting a Phase Portrait

I'm trying to plot a phase portrait for the differential equation $$x'' - (1 - x^2) x' + x = 0.5 \cos(1.1 t)\,.$$ The primes are derivatives with respect to $t$. I've reduced this second order ODE to ...
25
votes
2answers
2k views

Phase portrait on a cylinder

It is very nice and very easy to make a sketch of a phase portrait with StreamPlot. For example, for the classical pendulum, defined by \begin{eqnarray*} \dot x&...
2
votes
3answers
2k views

Phase portraits and StreamPlot

I typed StreamPlot[{y, x-x^3-0.3y+0.5Cos[1.25t]}, {x, -2.5, 2.5}, {y, -2.5, 2.5}] but all I got was a blank plot. What did I do wrong and can I fix it?
13
votes
1answer
835 views

Why isn't my Stream code plotting multiple solution curves?

My code is: ...
5
votes
3answers
943 views

Plotting the direction field of a differential equation

I have to sketch the direction field for the following differential equation: $$\frac{dy}{dx}=\frac{-0.02 y +0.00002 xy}{0.08 x-0.001xy}$$ This is the code I used, which gives an incorrect plot: <...
9
votes
1answer
293 views

How to plot a vector field on a geographic map?

Suppose I want to VectorPlot on a geographic map a vector field defined on a Reference Ellipsoid. The field is given to the following function as a ...
3
votes
2answers
374 views

Cleaner Approach to Plotting Multiple Solution Curves on Phase Portrait

I am trying to plot multiple solution curves onto a phase portrait. I used the approach shown here, but is there a cleaner approach? For example, can we just add a parameter $n$, that randomly ...
0
votes
1answer
584 views

Phase Portrait Trajectories

How do I make a phase portrait which looks like the ones demonnstrated here? Not the fancy version where I can use the controls to change it, just a screen-shotted version of say a spiral point? Any ...
2
votes
1answer
375 views

How to make program for phase portrait?

I need to add a phase portrait to my program. The program is below, and I need to create a graph like the one in the picture. My step size needs to be 5, from x0,y0 = 10 to x0,y0 = 50. ...
2
votes
1answer
168 views

Graphics Grid Direction Field Animations as GIF

I want to create a graphics grid as in this example below, but for the manipulate example below and store that as a playable gif file. Is this possible (I would like to see each grid location running ...