Tagged Questions
5
votes
2answers
174 views
How to graph a series of coupled oscillators and watch the wave move along them
Here are the differential equations that set's up the 11 coupled oscillators.
...
0
votes
0answers
35 views
How can I solve this differential equation for some restricted domain and plot the solution for some values of the parameter
I have encountered some problems when solving this DE. I am wondering if anyone could help me point out the mistakes.
The question says:
Obtain and verify a symbolic solution for ...
-2
votes
0answers
84 views
Phase space Plot [closed]
Using Mathematica 8 EquationTrekker is not working.
Could anyone please help me to find how the phase space will look for this vector fields?
...
0
votes
2answers
138 views
Plotting geodesics of upper half plane
I want to solve (numerically) the geodesics of the upper half plane and plot. The results are quite known (i) straight lines parallel to $y$-axis and (ii) semicircles centered on the $x$-axis. Now the ...
0
votes
1answer
165 views
DAE - varying initial conditions
I want to solve a DAE-system and I want to vary more than one initial conditions and to manipulate them. I looked here:
Putting NDSolve into ParametricPlot
But it does not work:
...
3
votes
2answers
220 views
Plotting heat equation in a Manipulate expression
I have a 2D heat equation $u_t = \alpha (u_{xx} + u_{yy})$ with conditions:
$u(x, y, 0) = 300$,
$u_y(x, 0, t) = \mu_1(x)$,
$u_y(x, 1, t) = \mu_2(x)$,
$u(0, y, t) = \mu_3(y)$,
$u(1, y, t) = ...
0
votes
1answer
86 views
8
votes
2answers
357 views
Basins of Attraction
How does one shade the basin(s) of attraction of a phase plot in Mathematica? I have been trying to do this using the system
$$\begin{align*}
\dot x &= y\\
\dot y &= -9\sin(x) - 0.20y
...
2
votes
1answer
107 views
Non linear equation phase space
As a supplementary to my question solution of differential equation I post a new question of how is it possible to make a Table that has elements the solutions of a non linear differential equation, ...
1
vote
1answer
144 views
Problems with NDSolve and stiffness
I am trying to solve an ODE in chemical kinetics:
$$\begin{align*}
\frac{\mathrm d[x]}{\mathrm dt} &= -k_1 [x][y]\\
\frac{\mathrm d[y]}{\mathrm dt} &= k_1 [x][y] - k_3[y]
\end{align*}$$
My ...
2
votes
1answer
113 views
Plot differential equation system in a complex way
Based on this differential equation system:
$$\begin{align*}
\dot{x}&=f(x,y)\\
\dot{y}&=g(x,y)
\end{align*}$$
where
$$\begin{align*}
f(x, y)&=x^2+y^2-25\\
g(x, y)&=x^2-y^2-7
...
0
votes
1answer
104 views
2
votes
1answer
116 views
ParametricPlot3D doesn't appear
Here I have one simple system solvable with NDSolve. I don't know why ParametricPlot3D doesn't present trajectory in space. I have solutions for x[t], y[t] and z[t]
...
4
votes
1answer
77 views
How can I highlight the vanishing-partials in an interactive 3D plot?
I am using Manipulate and Plot3D to plot a function with two real variables and two extra parameters.
...
2
votes
2answers
161 views
Solving and plotting ODEs while varying one of the initial conditions
How can I vary an initial condition in the numerical solution of a system of ODEs and then make a 3D plot of the solution space with that condition as one of the variables.
...
3
votes
2answers
252 views
How do I plot a solution of a differential equation?
I am having trouble generating a plot for a solution to my differential equations. I always end up with just blank axes.
...
0
votes
1answer
170 views
Solving the wave PDE using the Fourier method
I am trying to solve the wave PDE using the Fourier method and I need to animate the plots of the partial sum of order 45 -- U45(x,t) with initial conditions U45(x,t0), {t0, 0, 12, .2}.
I am ...
3
votes
2answers
124 views
Evaluate an ODE for several values of a coefficient and draw all the solutions in one plot
I want to draw one plot showing all the solutions the following ODE with different values of N. How can i do it?
...
2
votes
2answers
221 views
Plotting several numerical solutions plus the analytic solution of ODE in one plot
I want to be able to plot several numerical solutions of an ODE plus its analytical solution in one plot in order to see how the numerical solutions converge towards the analytical one w.r.t. the ...
10
votes
3answers
3k 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 ...
1
vote
3answers
525 views
How do I plot x[t] vs. x'[t] (where x[t] and x'[t] are solutions to NDSolve)?
I have a differential equation which I solved using NDSolve. I can easily plot x[t] vs. t, x'[t] vs. t, but....
how do I plot x[t] vs. x'[t]?
I tried using the Evaluate function to simplify things, ...
1
vote
1answer
231 views
How to plot population growth model?
How would I draw the graph of a function dy/dt=((Ry^2)/T)-Ry in Mathematica?
I have tried a few times but the constants are confusing me.
2
votes
1answer
211 views
Vector Analysis: Why are the Grad, Laplacian and Div being evaluated to zero
For the non linear partial differential equation below, why are the Gradient, Laplacian and Divergence being evaluated to zero despite using the VectorAnalysis ...
2
votes
1answer
120 views
Using MaxStepFraction as ticks on plot
Is there any way I could use the MaxStepFraction (or grid size) as used in NDSolve in the example below as ticks on the 3d Plot?
...
1
vote
2answers
215 views
Replacing variable in an equation with an Interpolating function polynomial and plotting residual
I was trying to plot the residual for the solution of my PDE. However, I was unsure about a couple of things.
I imported the data and created an Interpolation polynomial with ...
2
votes
2answers
346 views
Manipulate a Differential Equation result
I want to Manipulate the result of Differential Equation like :
...
2
votes
2answers
321 views
Interpreting the interpolating function and saving data to plot with external program
So far I have been solving non-linear pdes with NDSolve and then plotting the result with the in-built Plot3D and ...
5
votes
2answers
441 views
3- dimensional plot of 2-dimensional systems of differential equations
Let's take this first example of a 2D output:
...
2
votes
2answers
629 views
Animation of Differential Equations from NDSolve with ParametricPlot3D and Evaluate
I have a system of differential equations (referred to as "s") and use NDSolve to obtain the solution. I substitute the interpolated functions for the original ...
6
votes
4answers
1k 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 ...
0
votes
0answers
254 views
Unexpected result from contour plot - where is the color gradient?
When I plot a contour plot of my (in)famous code :P I get some unexpected results that I don't quite understand.
My code (the one that has ...
2
votes
1answer
209 views
Laplacian or Grad of an InterpolatingFunction
For obtaining a Schlieren image from an equation for density, I need to calculate the first derivative of density and make a contour plot.
The below code snippet calculates the first derivative w.r.t ...
1
vote
2answers
225 views
Plotting with NDSolve`StateData`
This question is a continuation of this.
As answered by J.M., I am able to iterate a solution.
However, I am unable to plot it.
I am sure that this has to do with my inability to understand how the ...
6
votes
2answers
405 views
Creating Plots for a Family of Solutions
I am wondering how do you set the parameters appropriately for $a_n,\,\alpha,\,\text{and }b_n$ to plot the family of solution of:
$u_n(r,t) = [a_n\cos(k_n\alpha t)+b_n\sin(k_n\alpha t)]J_0(k_nr)$
...
