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# 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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52 views

### How to solve a complex equation

I am trying to solve a complex equation for 'z' in terms of 'f'. At the moment my Mathematica is stuck running... Just wondering if anyone has any ideas, I know 0 < z < 40 if that helps. <...
91 views

### Can someone help me to solve this equation? [closed]

Solve[beta* phi *((1 + (1 - m)*alpha*theta ((phi^(-0.5) - 1)/((1 - theta)*phi^(-0.5) + theta)))) - delta == 0, phi] I run it and get nothing showing as results. ...
41 views

### Trigonometric derivation using Solve

Background: I'm trying to derive the relation between two variables in an optical system. The derivation is simple and well-known in the limiting case ($H \to \infty$, see figure), but rather tricky ...
49 views

### How to solve this equation by Solve?

I have an equation to be solved. But Mathematica does not work for it. I hope the solution x can be expressed as a function of a and b ...
50 views

178 views

### Solving partial differential equation involving Hilbert transform

While solving one research paper published in Physical Review Letters, I came across the following equation and I am unable to solve it. \frac{\partial f}{\partial t}−(\mathcal{H}(f)\left(\frac{\...
68 views

### Problems with manipulation

I am plotting geodesics on an ellipsoid. My problem is that I cannot do the manipulation, from a, b, c. From the starting point and the initial vector, the manipulation works well, but from the ...
68 views

### ListPlot3D of the results of FindRoot

I have a system of 2 simultaneous equations where i want to calculate the values of Tc and Tc which ranging with the values of two variables which are wfc and V. I tried to evaluate it by using ...
72 views

### Limiting solution space for symbolic algebra problems

I have a system of 12 quadratic equations with 12 variables (x11, x12, x21, x22, x23, x33, p1, p2, p3, ϕ, μ, τ) and several positive constants,w, q1, q2. ... > 0<...
73 views

### Vortex motion equation for flux-flow instability

I am solving the motion equation of an isolated vortex oscillation in a superconductor. I am assuming that the driving force is generated by an RF current oscillating at 1.3 GHz. The main point of ...
36 views

My code is ...
108 views

### Error messages for FindRoot and NIntegrate

I want to solve the following problem. First, the setup. A function $V(\varphi)$ defined as \begin{multline} V(\varphi)=\frac{\alpha-3}{4}e^{\sqrt{2\alpha}\varphi}+\frac{\alpha-5} {\gamma}e^{(\...
44 views

### NSolve cannot find solution to system of trig equations

I was making a program to convert a rotation matrix to a set of euler angles. I wanted to do this for any valid rotation order that the euler angles were made with, and I did not want to do it the ...
59 views

### Five equations to solve 6-variables question, is it possible?

I was given a task to find the value of variable a,b,c,d,e and f. But I'm not sure it is even possible, given that only 5 equations are available. Can anybody point out how to solve these: ...
66 views

### Still having problem with solving high polynomials with exponential equations simultaneously

I need to find the value of Ta and Tc for two simultaneous equations to get a numerical answer using NSolve. I have tried using FindMinimum and NMinimize and still could not solve the problem. Here is ...
59 views

### Why does Mathematica just return Hold of my Input? [closed]

Example: Solve[x^2 + a x + 1 == 0, x] Output: Hold[Solve[x^2 + a x + 1 == 0, x]] What is the problem? Any child can solve this in its head
150 views

### Solving BPV of second order nonlinear ODE through NDSolve

I'm trying to solve a 2nd order related ODE system in two region using Piecewise. BC: 1) y'=0 and at y'[1.6]=0 while at 1 <...
3k views

### Has Mathematica 12 gotten worse at solving simple equations?

Mathematica used to be easily able to solve an equation like this: Reduce[Log[Sqrt[k p]/Log[k]] == 0, p] (I can easily do it myself, at least I can find the ...
95 views

### Triggering WhenEvent as a result of WhenEvent

I'm attempting to solve a dead-simple differential equation with events: ...
34 views

### Solving equations, checking linear dependency of equations

I have the following input and try to do solve the equations for in total four unknowns. When I run the input only "solutions" for two of the four unknowns are given in the output. I am not quite sure,...
80 views

### Can not solve this question [closed]

Solve[beta*x *((1 + (1 - m)*sigma*theta ((x^(-1/2) - 1)/((1 - theta)*x^(-1/2) + theta)))) - S == 0, x] Can someone please help me, I don't know why x is not ...
36 views

### How do I plot the output of Solve as a function? [closed]

I have a system of equations (13 eq) and I want to solve for S. There are four solutions in terms of k and ...
118 views

### Tangent point coordinates when the curve is a set of points

I want to find the coordinates of the tangent point between a convex curve and a line that passes from a point with known coordinates (0,b) ("efficient portfolio" ...