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

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0answers
43 views

How to speed up geometric Resolve query involving $\exists$ and $\forall$?

I would want to test connectedness of semialgebraic sets with naive code like this: ...
0
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1answer
52 views

DSolve not outputting any result

I'm trying to solve a system of differential equations using DSolve, but I am not getting any output beyond a repetition of my input: ...
0
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1answer
65 views

Manipulate Solve

I have seen similar questions and answers but it did not help me. I would like to see effects of three constants in equations resulted from solve command. conditions are ...
1
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0answers
31 views

Tracking solutions over a Brillouin zone

Thanks to @bbgodfrey I have a function that finds the two solutions to a set of equations bounded by a hexagonal region (corresponding to the Brillouin zone). It takes the angle ...
0
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1answer
87 views

In which condition releated to thee coefficients some equation has a solution

Please excuse me if the question seems to commonplace. Can Mathematica give a response to this question: In which condition related to the coefficients $c>0, \, n\geq 2, 0<p<1,\, a>c$ ...
0
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1answer
76 views

Add assumptions to Solve command

I want Mathematica to solve the following by assuming the part within the Log function, which is ...
0
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0answers
66 views

Difficulty solving an equation involving a couple of different powers

I have this semi-complicated equation to which I want to find an analytical solution for $\epsilon$. The equation is a s following: $$a^2 (2 b k \epsilon \sqrt{1 - \epsilon^2/b^2} - 2 c k ...
0
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1answer
72 views
0
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1answer
603 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: ...
0
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1answer
126 views

Formatting an equation: X^Y to pow(X,Y)

I am trying to solve for the intersection of two circles with arbitrary centers and arbitrary radii. ...
0
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0answers
25 views

Convert the output of solve into equality [duplicate]

I know this is has been asked before but seriously, none of the ones I checked helped because they referred to a single variable assignation. Apologies if this is a duplicate. I have many variables ...
2
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1answer
57 views

Mathematica - Count number of zeros of a function in an interval

Let's say I have a function, F[x_,d_] = Sqrt[(x^2 - 1)^2 + d^2], and I want to count how many roots (no root, or one root, or two roots etc.) it has in an ...
0
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1answer
63 views

numerically solving

I am trying to solve for [Lambda] as a function of a (unknown) from this expression ...
1
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3answers
94 views

Finding roots of transcendental equation and collecting into a list

I am working on a physics reserach project for school and I have run into some troubles working Mathematica. I am a fairly inexperienced mathematica user so any help would very much be appreciated. I ...
3
votes
3answers
117 views

Reduce gives wrong solutions

Given the follwing system of equations eqs = { x/(x - 2) - 4/y == 1, x/(2 + 1/y) == y/(3 - 1/x) } Although the domain of this system does not contain ...
6
votes
2answers
175 views

How to reverse irreversible function in Mathematica?

How to reverse formula $y(x)=x (\frac{1}{sin \frac{\pi x}{2}})^\alpha$ i.e. express it as $x = x(y)$ in Mathematica? I did this way ...
0
votes
1answer
45 views

Setting the solutions of an equation as a variables [closed]

This is probably a simple question, but i couldn't find a solid answer. So i have an equation Solve[{F[x, y] == 0, G[x, y] == 0}, {x, y}] but i want to use the ...
1
vote
2answers
54 views

RegionPlot after Reduce

I have a problem in this form To solve this I have tried this f1[y_] := 2 - (y - 1)^2; f2[x_, y_] := x + 1 - (y - 2)^2; f[x_, y_] := Max[f1[y], f2[x, y]]; The ...
2
votes
2answers
588 views

How to make a Dynamic Calculator to solve a quadratic equation?

Taking my first steps in the world of Mathematica Programming. The aim of my program was to modify Wolfram's dynamic calculator (which performs an addition subtraction and a product - in response ...
-2
votes
1answer
53 views

Solving fifth order polynomial equation [closed]

I am trying to solve this equation: 1/s^3 + 3s^2 + 4s + 1 But I am not able to solve it. A little help would be appreciated. P.S: I am new to Mathematica and I ...
0
votes
1answer
76 views

Transcendental Equation

After playing around with The Planck radiation law for the spectral energy density, (differentiation and setting equal to 0 to find the maximum wavelength"x") I'm stuck on how to deal with what I'm ...
2
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1answer
63 views

Faster variant of Reduce for finding zeros of holomorphic functions in a region

I'm currently using Reduce to find zeros of a function in a region on a complex plane: ...
1
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1answer
114 views

Approaches to solving non-linear systems of equation with assumptions

The specific type of system looks as follows: \begin{align} (r-r')x+4d_1 x^3+4d_{12}xy^2 &= 0 \\ (r+r')y+4d_2 y^3+4d_{12}yx^2 &= 0 \\ \end{align} Where $r,r',d_1, d_2, d_{12}$ are all real ...
1
vote
2answers
69 views

Confusion in Numerical Integration while using FindRoot

I used this code for numerical integration NIntegrate[(x^2 - .0015 x^4)/D[(x^2 - .0015 x^4), x], {x, 1.414, 13}] when upperlimit of x is 13, the integral value ...
4
votes
1answer
52 views

Sequential System of Equations

I’m trying to set up this system of equations that sequential feeds into itself. I have these 2 equations I’m running. I’m new to Mathematica so I have no idea how to even start this. The basic idea ...
0
votes
1answer
51 views

Roots of a transcendental equation

I need to find the 50 first roots of a transcendental equation. I use Table and FindRoot, so I find repeated positives and negatives values in a list, but I want only the 50 first positives and ...
0
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0answers
135 views

Solve doesn't solve my transcendental equation

I want to solve a geometry problem. To do this, I need get formula for "d" in the equation: ...
0
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0answers
70 views

What does it mean when FindInstance returns unevaluated?

According to the documentation, FindInstance[] return the empty set when it does not find a solution and one of the examples claims that this is proof that no solution exists. So if FindInstance[] ...
0
votes
0answers
65 views

First Order Conditions

I am new to Mathematica so I am not sure if this is correct. I have setup up a Lagrangian and I am trying to get the FOCs of this problem. However, it does not seem to work. Any help would be much ...
0
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0answers
57 views

Find first n roots of a function

Is there a straightforward way to find the first $n$ roots of a function? I have found various ways of finding roots in an interval, but none that would keep looking for roots until they find a ...
1
vote
1answer
83 views

Improving Performance - Finding Polynomial Roots [duplicate]

I'm fairly new to Mathematica. In the past, my usage has mostly been limited to solving the occasional equation, making some plots, and working with small scaled statistics. None of these have been ...
0
votes
1answer
120 views

Time evolution of a wave packet from the time-independent Schroedinger equation [duplicate]

Starting off with the time-independent Schroedinger equation (TISE) $\quad \quad -\frac{\hbar^2}{2m} \nabla^2 \psi + V(r, \theta) \psi = E\, \psi,$ I would like to study the time evolution of an ...
0
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0answers
29 views
-2
votes
1answer
51 views

Solve on parametric equation produces inequal results

I have a parametric (parameter t) equation in two dimensions (vectors). s = Solve[pt[t] == qt[t], {a, b}] Both pt and qt are parametric lines using a and b as ...
1
vote
1answer
174 views

How to plot the graph of the equation F[x,y]=0 if y is real number, x is complex? [closed]

I have an equation F(x,y;a,b,c,...)=0, where x and y are variables, a,b,c,... - parameters. y is a real number, x - complex. For every given y I need to solve this equation, i.e. to find Im(x) and ...
0
votes
2answers
40 views

Expand “hierarchical” system of equations

I have a system for equations that is structured hierarchically: - Level 0: these are base variables that I can measure from a process (e.g. a,b,c) - Level 1: these are variables derived from Level 0 ...
0
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0answers
49 views

No solution for a system of equations

I am a newbie in Mathematica and I face a problem in my attempt to solve a system of equations. The system is the following: ...
1
vote
1answer
86 views
0
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1answer
35 views

Strange behaviour of Append [closed]

I have the following situation and I completely do not understand why the second system can be solved but the first (of the same equations, as it seems) cannot. How is it possible? ...
0
votes
0answers
27 views

Problem evaluating function

Hey there I am missing the trick in evaluating following problem so that mathematica first solves the derivative of the legendre polynom and just after that it solves the whole thing for value 1 ...
0
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0answers
41 views
0
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0answers
69 views

Solving symbolically large system of underdetrmined linear equations

I would like to find matrices 3x3, say A, B, C, such that for all symmetric matrices X, with zero trace, one has: $$AX_1+BX_2+CX_3=0, AX_2=BX_1, AX_3=CX_1, BX_3=CX_1$$ where $X_i$ denotes i-th row (or ...
1
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1answer
80 views

Complicated equation solving

I want to find the maximum point or optimal value $y$ of Rx1[y_, a_, b_]. ...
0
votes
1answer
66 views

Finding gradient of equiangular (logarithmic) spiral

I encountered a problem in determining the gradient in cartesian coordinates (x,y) of a logarithmic spiral (or equi-angular spiral) profile. The log-spiral definintion is as shown below (similar to a ...
0
votes
1answer
93 views
2
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1answer
80 views

Stability Boundaries via Routh-Hurwitz Criterion

I'm attempting to determine the stability boundaries of a 2nd order system via Routh-Hurwitz stability criterion. That is to say, I need to compute when a polynomial, which is in terms of variables ...
2
votes
1answer
114 views

Can Mathematica solve this type of recurrence?

I have the following recursively defined equation: ...
0
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2answers
63 views

Diophantine and odd

need to resolve this Diophantine equation, but with the condition that a, b, c belong to the set of odd numbers from 1-51, as I write this condition in the code ...
0
votes
0answers
24 views

Some more efficient form to calculate the order value

This takes a long time, any idea how accelerate Reduce[x^(2 x^2 - 2 x) - 1 == x , x] k = x^2 + x^-2 k = ?