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

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1
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1answer
74 views

Solving a complex logarithmic equation

I am trying to solve the following equation for $x$, with integer $n$. (1 - ((-1 + x)^E x^(1 - x) Log[x]^-E)^(1/(-1 + E)))/(-1 + x) == n
0
votes
0answers
58 views
19
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4answers
813 views

Hightlight all the self-intersections of a Lissajous figure

This graph–also known as a Lissajous figure–contains so many self-intersections.How can I highlight them? ...
0
votes
1answer
40 views

Solve and NSolve hitting iteration limit for simple system [closed]

I'm am trying to get Mathematica to determine the intersection of a line and a parabola, like so: Solve[{x + y == 6, x^2 == y}, {x, y}] But evaluating this gives ...
0
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1answer
50 views

Question about a catalytic equality?

I have a question on math.SE that explains how I came up with these equations. ...
2
votes
1answer
72 views

Reduce / Solve cannot solve simple equation

Why does Reduce[{a^b*c^b == c, 0 < b < 1, a > 0, c > 0}, c, Reals] give ...
2
votes
3answers
118 views

Find roots of a peak to calculate its width at 10% peak height

I have numeric data points (x,y) values from a peak. I constructed a interpolation to get an interpolating function. Interpolation[data] What I want to do is the ...
0
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1answer
36 views
0
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1answer
41 views

Recursion depth and solving equations using Solve

I am trying to solve an equation: ...
1
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2answers
184 views

How to Fit experimental data with 4D ParametricNDSolve?

Let me first explain the background problem. I'm trying to solve a problem with a projectile motion in 4D such that the position vector is: $\boldsymbol{r}(t)=\boldsymbol{r}[x(t),y(t),z(t)]$ I have ...
0
votes
1answer
50 views

Solving a vector equation [duplicate]

I want a simple and intuitive way of solving for $t$ given that $\mathbf{i},\, \mathbf{j},\, \mathbf{k}$ are the unit vectors in $\mathbf{R}^3$. $$ 5 = (2 \mathbf{i} - 3 \mathbf{k} + (\mathbf{i} - ...
4
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5answers
226 views

On finding all the positive integral solutions of $x^2+y^2=z^2+1$

I am a new to Mathematica. My goal is to find many (if not all) positive integer solutions to the equation: $x^2+y^2=z^2+1$ using Mathematica. However the problem is that I can only find a ...
0
votes
0answers
60 views

How can I be sure Solve failed because there was no solution to be found?

Is there a way I can be sure that the reason Mathematica can't find an answer is because there isn't one, rather than because I made a mistake with the code? The system is as follows. ...
3
votes
2answers
176 views

Creepy numerical artefacts of a closed-form solution

I'm wishing you a nice day and here is my problem: I tried to obtain relation between chemical potential and temperature in a semiconductor and I arrived at this equation: $$ 2 e^{-\Delta/kT} \left( ...
0
votes
1answer
47 views

Can't NSolve system of exponential and linear equations in several variables

At the moment I am stuck with the following code, when specified to use root , quadratic or log utility functions all it fine, only exponentials like: $\small \left\{-e^{-c_{0,1}}-0.25 ...
0
votes
0answers
43 views

Solve equations for derivatives

I want to solve some equations in General Relativity numerically with the Runge-Kutta method. Therefore, I need to solve for example $r^{''} \left(\tau\right) + t\left(\tau\right) + a = 3 $, where $ ...
0
votes
0answers
51 views

Computing the coefficients for Gaussian integral

I wrote a small script to find the Gaussian integral points and weights: ...
0
votes
0answers
93 views

NSolve and Loop - getting error that does not occur with single instance

I am having difficulties getting this code to work. Code: ...
0
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0answers
55 views

Plot zero contour of a function of two variables

I have F[x_,y_] = f(x,y). I would like to solve (numerically) F[x,y] == 0 to give x as ...
1
vote
1answer
63 views

Computing a recurrence table backward

I am trying to understand how to compute a recursive equation backward say n = 10 to n = 1. I am trying to solve a PDE for which ...
0
votes
0answers
20 views

Solving (one variable) Linear Equation by Dividing Slope by Constants Accumulation? [migrated]

I've been Google searching for this, and apparently my Googlefu is not strong today, or I'm doing something wrong. I have been told that it is possible to solve a one variable linear equation by first ...
1
vote
1answer
326 views

Usage of Piecewise/RSolve to solve an equation based on condition

I am trying to compute price of call option on a stock using the finite difference method. I have a VBA code for it, and I am trying to find out how I can use Mathematica memoization functions and ...
1
vote
1answer
74 views

Solve system of equations with implicit function [closed]

I am trying to solve a system of 3 (non-linear) equations with two variables $x,\ y$ and one unknown function $f(x,y)$ of these two variables. Also, the system includes the change of this function $f$ ...
1
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3answers
81 views

Getting a list of x coordinates of intersection points of two functions

I have two functions, f[x_] := 5 Sin[2 x] g[x_] := (5 x + 2)/(x + 2) I am trying to find the x coordinates that intersect ...
0
votes
0answers
36 views

Deciphering output messages using Solve

I'm trying to solve the following system. The error messages I'm getting suggest that there may not be a solution [my desired result], but I'm not sure if there could be something else going on. The ...
1
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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
votes
0answers
42 views

RSolve with two variables

I want to find $a(m,n)$ with $~a(m,n)=\alpha * a(m-1,n) + \beta * a(m,n-1)$, where $\alpha$ and $\beta$ are constants. I expect an explicit $a(m,n)$ represented by $a(0,j),~j=1,2,\cdots,n$ and ...
0
votes
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
74 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
33 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 ...
6
votes
2answers
177 views

How to read complicated result from Reduce?

How can I read this Reduce output from Mathematica that I got from solving an inequality? I do not perfectly know when one case in this case analysis is over and ...
0
votes
1answer
102 views

RSolve with integrations

I want to solve this question with Mathematica. $$T_0(t)=c(t),\quad T_n(t)=a\int_0^t T_{n-1}(s)\, \mathrm{d}s+b(t).$$ Is it possible to solve $T_n(t)$ with ...
0
votes
1answer
77 views

Add assumptions to Solve command

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

Equation solving problem [closed]

I have this code: ...
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 ...
0
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1answer
51 views
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
127 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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1answer
63 views

numerically solving

I am trying to solve for [Lambda] as a function of a (unknown) from this expression ...
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
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 ...
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 ...
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 ...
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 ...
-2
votes
1answer
54 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
votes
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: ...
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 ...