# Questions tagged [equation-solving]

Questions on the analytic and numerical equation solving functions of Mathematica (Solve, Reduce, NSolve, FindRoot, DSolve, RSolve, etc.).

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### While solving equations I'm getting error [closed]

These pictures give you the governing differential equation to solve with boundary conditions. While I'm solving the equations I'm getting an error.
1 vote
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### Unexpected Peaks and Detours in PNJL Model Plot Using FindRoot

I'm working on a numerical solution for a PNJL model. The model I’m working on is based on the formalism described in this paper: arXiv:hep-ph/0506234. My goal is to reproduce plots similar to the ...
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### I have problem with my code [closed]

I don't know why it's not running this code : ...
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### Numerical Solution to Euler Lagrange Equation [closed]

I am quite new to wolfram. would anyone share how to solve the euler lagrange equation (equation at the bottom), by using variables from equations above. thank you
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### How to find conditions such that solution to linear system of equations exists?

Say I have some complicated equation that contains some constant variables like this ...
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### Solving a matrix differential equation with change of variable

In order to solve $\partial_t X(t) = -i(M X(t) - X(t) M^*)$ (where * is conjugate-transpose), I wrote the following code: ...
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### Finding Jacobian from Hamiltonian

Suppose I am given a Hamiltonian. How do I find the Jacobian from the Hamilton equations of motion? Here is what I have done so far: ...
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### NSolve uses all CPU resources

Is it default setting of NSolve that it uses all my four cores of CPU? Be aware that the following code made my computer non-respondent for about 18 seconds till it ...
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### Finding Lyapunov exponents from Hamilton formalism [closed]

I have the following Mathematica code to find the Lyapunov exponents for a given Hamiltonian. I use an algorithm developed by ChrisK for my code given below: ...
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1 vote
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### Getting conditions for existence of trigonometric solutions

Consider the following problem. Define a trigonometric function f(x): f[x_]:=a*Sin[2*x]+b*Cos[2*x]+c*Cos[x]+d*Sin[x]-e We want a range of $x$ for which $f(x)\leq 0$...
1 vote
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### Solution Of 2D Logarithmic PDE In Periodic Potential In Imaginary-Time Propagation Method

I am trying to solve Eq.no.(8) from https://arxiv.org/pdf/2009.06804 and generate Fig. (3)-(4). The problem I am facing is that in imaginary time propagation method the solution is growing with time ...
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### How to use Lagrange multipliers to find the maximum value with constraints?

How can the Lagrange multipliers method be employed to optimize the function?$f(x_1,x_2)=(x_1^p+x_1^p)^{1/p}$ subject to the constraint $g(x_1,x_2)=p_1x_1+p_2 x_2-y=0$ I am a beginner, and the results ...
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1 vote
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### Solving a system of two equations for only real solutions

I have a system of two equations \begin{align} \frac{1}{2}A &= \frac{2.5 T}{\sqrt{-(\frac{\pi^{2}}{3} + 2\mu)}}, \\ \frac{1}{2}E &= \pi T + \frac{\mu}{2}A \end{align} in which $A$ and $E$ are ...
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### Any other better way to draw a dynamic tangent to a curve? [duplicate]

I want to draw a dynamic diagram of the tangent line at any point on the curve y = =Log[x]. ...
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### Duffing Equation:Transition to Chaos

I create the following code but the results were not that I expected for. The paper I study is Duffing Equation My code gives me the following. But I want a smoother and clearer plot. What should I ...
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### Solving expression with incomplete gamma function and plotting

In the following code I want to plot fplot1 vs P by substituting r from ...
I have the following function that I want to invert to use in further calculations, i.e. I need to be able to plug in the expression $r = r(p)$ in further calculations where $r$ goes over the range ...