# Tagged Questions

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### Plotting Geodesics in Kerr

I'm interested in plotting the trajectories of null geodesics near a rotating black hole (given by the Kerr solution) which involves a system of first order differential equations. Some Context (not ...
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### Trouble outputting Plot

I am trying to solve a system of ODEs and plot them with Manipulate but I keep getting blank outputs. Below is my code: ...
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### How do I subtract two contours?

Suppose I have this contour described by the equation the root $z$ of this equation $\frac{1}{x^2 + y^2} + \frac{1}{xz} = 2y$ Now suppose the equation is tweaked slightly, with an addition of $w$, ...
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### Help to plot Poincare section for a system of delay differential equations

I'am trying to plot Poincare section for a 4-dimentional system of Delay differential equations. I don't know how to specify initial conditions. Can I use each of the code in the following ? Also how ...
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### Problem with Poincare section

these are equations for some double oscillators: $x'(t)=p, p'(t)=-x-3y, y'(t)=q, q'(t)=-y-3x$ I would like to plot the Poincare section for collection of $(y,q)$ when $x=0$ and $x'(t)>0$ (or for ...
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### Problem with Plot and ParametricNDSolve

This is my first question on this site, I hope it is written in an understandable way. Let's start. My aim is to plot a certain parametric region, with $x$ and $y$ coordinates given by the following ...
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### How to visualize slope fields of differential equations without vectors?

I'm looking to visualize slope fields of differential equations for my differential equations course. Every example I see draws them as vectors, adding unnecessary "arrows" that, to me, are visually ...
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### Plotting basin boundary

How to plot the basin boundary in Mathematica? I have been trying to do this using the system ...
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### Plotting DSolve results

I am attempting to make a plot of the solution an ODE. I want to plot the solution using PolarPlot, x is the polar angle in ...
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### Linear Stability Analysis Routine. Normal Modes in NDSolve

I want to make the linear stability analyis of a nonlinear system of PDEs. So for example then I want to plot what happens to the amplitudes of the modes. To do that I need to solve my equations with ...
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### How to draw the image of a circle under the action of a transformation of the phase flow?

How to draw the image of a circle $x^2+(y-1)^2<1/4$ under the action of a transformation of the phase flow for the equation $\dot{x}=y,\ \dot{y}=-\sin x$? Here $\dot{x}$ means $dx/dt$. Any help or ...
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### Getting clearer StreamPlot output

When I do a StreamPlotof a rather complicated pair of differential equations, it loses some details. For example: ...
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### StreamPlot using NDSolve gives error messages

StreamPlot[{x[0], x'[0]} /. NDSolve[{x''[t] == 1, x'[0] == v0, x[0] == x0}, {x, x'}, {t, 0, 1}], {x0, -2, 2}, {v0, -2, 2}] The above code gives me the errors ...
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The solution and plot of the Differential equation is $\frac{d^2S(r)}{dr^2}+\frac{1}{r}\frac{dS(r)}{dr}-S(r)+3S^3(r)=0$ ...
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### plotting the solutions of system of differential equations [duplicate]

The following code include the system of differential equations: ...
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### Plot basins of attraction using separatrices for particular pendulum

How can I plot the stable and unstable separatrices to make a graphic of the basins of attraction of this differential equation? ...
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### How to increase Maximum number of steps in any other functions except NDSolve?

I want to plot an output response from a state space model. I use StateResponse[] to calculate it and then plot it. When I run my code, I face this message: ...
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### 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. ...
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### 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 ...
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### 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: ...
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### 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) = ...
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