# Tagged Questions

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

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### How to solve an equation with previously set variables

I am trying to set up an equation with multiple variables and use the Solve function to simplify it and plot the result. However, when I plug in my equation to the Solve function, it just gives me an ...
30 views

### Make NSolve faster by keeping only one solution

Dear Mathematica users, NSolve usually returns all numerical solution it can find. When a variable is squared in some equation, ...
68 views

### How to solve time dependent pde?

I have set out to try and solve a time dependent wave equation with specific boundary conditions, but I am running into a bit of a snag. As you can see, I am trying to solve for the wave function u[t, ...
62 views

### Robust FindRoot search

I have the following simulation that models a rocket landing (flat Earth, no atmosphere, constant gravitational acceleration), which uses root finding to figure out when to start and stop the engines ...
87 views

### Solving and Plotting Infinite sums over solutions to transcendental equation involving Bessel functions

I am trying to use Mathematica to plot the following equation $E(q,\Delta)$ vs $qa$, for set values of $D \Delta/a^2$ and $\bar\rho a/D$. I have looked at other stackexchange posts which deal with ...
321 views

### How to solve an equation with a nested function

I have the equation f[f[x]] == 28 + 9 x How can I solve this for f[x]? I note that this post relates to the topic, but ...
117 views

### Solve returns empty list

I want to solve these equations but Mathematica gives no answer. ...
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### Please check my code for gauss elimination and rectify the mistake [on hold]

clc; clear all; prompt = 'Enter No of Unknowns \n' ; m = input(prompt) ; a = zeros(m,m) ; x = 0 ; for x = 1:m for y = 1:m prompt = 'Enter element(x,y) \n' ; ...
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### Solving Inequality with Exponentiation and Log [on hold]

I have an inequality that I am not able to proove which is $Log[d] <\frac{(-1 + d^M) (d^M - d^N) N} {d^{M}(-1 + d^N) M (M - N)}$ with $0<\delta<1$, $M\geqq1$, $N>M$ and thus $N>1$. I ...
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### NSolve/Reduce Help: 3Equations/5Variables

I have this system of equations that I have been trying to solve using Mathematica; I had been running this last evaluation for 30 hours and my computer crashed :/! So, instead of deciding to run ...
44 views

### Probems using 2 For and a AppendTo to cycle through my Equation to solve some matrixes

I am trying to solve a few problems here. I have an equation with multiple variables that I am trying to solve in For loop method. I will attach the file below. In addition I am trying to get it to ...
59 views

### Expectation of Largest Roots of Bernoulli distributed coefficient Monomials

I am interested in determining the most probable maximum values of the real roots of polynomials of form $P(x)=\sum_{k=0}^n a_{k} x^k$ where the degree $n$ will have a defined value (say 3,4,5...) and ...
85 views

### how do I control the output of Reduce function?

Reduce[x*y > 50 && x*y < 100 && x < 100 && x > 1 && y > 1 && y < 50, {x, y}, Integers] what if I want ...
59 views

### Solving a polynomial where variables are constrained to take only some values

I want to find out which combinations of 1's and 0's would make this kind of equation be null: ...
87 views

### How to solve algebra equations containing integration and parameters?

I'm trying to solve two nonlinear algebra equations for two unknown parameters, U and Tf. Since some terms in these equations contain integration, and the integration also contains U and Tf. The main ...
69 views

### How can I solve my system of simultaneous polynomial equations?

I want to solve the system of equations (y + 1)(a - x^p*y^q) == 0 (y + 1)x^p*y^q - c*y == 0 But I am getting the massage this system can't be solved by ...
33 views

### Why Mathematica does not Maximize when using parameter

I have recently started using Mathematica and I have got a question using it. I would appreciate if one could help me figuring out how to handle it. I have the following simple maximisation code <...
166 views

### Intersection coordinates of two spheres

I am trying to obtain a list of coordinates at which two spheres intersect. Take for example the spheres: sp1=Sphere[{0, 0, 0}, 1] and ...
131 views

### Finding “nice” solution for under-determined system with constraint?

Consider the following equation: ...
213 views

### Solve a system of M equations without specifying M [on hold]

I am trying to write my game-theoretic model in Wolfram Language. There is only one remaining step and I am not sure if it is within reach of Wolfram Language (or Mathematica). I describe a simplified ...
1k views

### How can I solve the equation with integers as a solution?

I want to solve the equation $$(x-1)^2 + (y-1)^2 + (z-1)^2 = 49$$ where $x$, $y$, $z$ are integer and $x \neq 1$, $y \neq 1$, $x \neq 1$. How do I tell Mathematica to do that?
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### solve equation with integer maximum [closed]

how to solve with Mathematica a)$\left [\kern-0.10em\left[ 5 x \right]\kern-0.15em\right] = 2x+1$ b) $\left [\kern-0.10em\left[1/ 5 x \right]\kern-0.15em\right] > 2x+1$ EDIT = double ...
88 views

In my project I need to solve following equation analytically could anyone help me ? As I read the other questions, my equation seems like Helmholtz equation $$\triangledown^2 u(x,y) - k_cu(x,... 1answer 932 views ### Solve non linear system of equations I am trying to solve a system of two equations with two unknowns. In these equations I have, a part from constants: Unknown nr 1,$$D_{\perp}$$Unknown nr 2,$$\omega_C$$Known function of r:$$\mu(...
I want to solve an equation which contains an infinite continued fraction $F(n)$. Then I must (obviously) truncate this continued fraction at $n=2000$. The problem here is that Mathematica does not ...