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

learn more… | top users | synonyms (4)

0
votes
1answer
274 views

Iterative way to find roots of confluent hypergeometric function

I am trying to find roots of confluent hypergeometric function and I wonder if I can choose the initial guess by the choice of $\beta$. ...
0
votes
0answers
17 views

What methods does Solve use?

Could you tell me which method that Solve applies to solve linear and polynomials equations?
0
votes
0answers
35 views

Difficult to solve the equation using FindInstance and not able to solve it numerically

I hope to find the range of a which leads to non-zero solution of H when you are given a specific value of B. And I hope to get ...
0
votes
0answers
60 views

Best way to determine polynomial coefficients in series expansion

I would like to solve the equation $$h'(\boldsymbol{x}_1)\left[B_1\boldsymbol{x}_1+g_1(\boldsymbol{x_1},h(\boldsymbol{x}_1))\right]=B_2h(\boldsymbol{x}_1)+g_2(\boldsymbol{x}_1,h(\boldsymbol{x}_1))$$ ...
0
votes
1answer
95 views

Solving a Trigonometric parameter

I have a similar case as given before : Solving a Trigonometric function with one parameter Let: m = 1; Dx = 100; ν = 0.25; b = 1; and, ...
0
votes
0answers
52 views

Using Solve but getting no output

I am trying to solve a model using a constant-elasticity-of-substitution production function, but when I try to solve the first order conditions, I just keep getting back what I typed. ...
0
votes
0answers
37 views

Step by step solution of an equation [duplicate]

How I solve this system of equations STEP BY STEP in mahematica. \begin{align} (x + 1)^2 [(p - l)^2 + (q - m)^2] &= (a - l)^2 + (b - m)^2 \\ (x + 1)^2 [(p - a)^2 + (q - b)^2] &= x^2[(a - l)^2 ...
0
votes
0answers
32 views

Resources/ best practices for exploratory economic theory work

This is a little general, so I will try to make it as specific as possible. I used Mathematica a fair amount to derive and check analytical solutions to problems in theoretical economics. Lots of ...
0
votes
0answers
30 views

How can Mathematica solve 7 equations and want to find 7 variables [duplicate]

I have 7 equations as below * e1 := (1 - a) p Subscript[A, 0] Subscript[s, K ] ! *SubsuperscriptBox[(s), (L), (-a)] = (1 - b) Subscript[B, 0] (1 - Subscript[s, K]) (1 - Subscript[s, ...
0
votes
0answers
29 views

What is that Root[…] inside the answer represent? [duplicate]

So I am encountering this situation, in which mathematica doesn't give me the answer, but in a form of "Root". How do I interpret this ? what is the number after the "&" represent? How should I ...
0
votes
0answers
46 views

Finding Roots of Non-linear Systems: Rescaling polynomials

I'm trying to get all isolated finite equilibria of a moderate multi-dimensional non-linear system of equations. Particularly I have 9 independent variables and third order at most. It turns out that, ...
0
votes
0answers
97 views

NSolve for large models

I'm a Mathematica rookie running version 7.0 for Mac OS X x86 (64-bit) (February 19, 2009) on a 2010 MacBook Pro. (I'm also a stackexchange "newbie" who originally posted this on stackoverflow, thus ...
0
votes
1answer
41 views

How to use an output of a Solve function in further calculations? [closed]

Following is the polynomial equation that gives me a single real root: ...
0
votes
2answers
54 views

Eigenvectors inside a maniupulate function

I am trying to make a physics application and it requires that the eigenvectors be taken for a 3x3 matrix. It is my intention that Mathematica never have to deal with the matrices symbolically. ...
0
votes
0answers
34 views

Replace parameter of NDSolve by a Function

I dont know how to replace the paremeter inside of an interpolation function result from NDSolve by a function of another parameter. This is it: I have a ...
0
votes
0answers
46 views

Calibrating a difference equation system

Sorry for not posting it in the first attempt properly. Consider the simple problem of a first-oder difference equation: ...
0
votes
0answers
35 views

How to solve equations over polynomial rings

sorry if my question is very basic but I don't know what to even search to look it up and the only "obvious" places I thought of had nothing. Some background, for whatever context it might provide. ...
0
votes
0answers
40 views

Coupled ODEs with boundary conditions - DSolve Error

I'm relatively new to mathematica and I can't find the error here. I suspect it has something to do with the fact that vx, vy, vz aren't blue on my mathematica - as in, they already have some assigned ...
0
votes
0answers
82 views

To solve an equation

I am trying to solve the equation: Solve[Re[Integrate[(2 c - (r^2) Exp[- I 1.4746])^(0.5), {r, 0, 31.7576}]] == 2.1216, c] I want to integrate an expression in ...
0
votes
0answers
69 views

NIntegrate: integrand has evaluated to non numerical values

I have pasted a code that has been giving me some trouble and errors when I try to compute. ERROR: "The integrand 1435.1232 E^(-6.4703566*10^6 s^2) deEntrance[s,phi]^2 has evaluated to ...
0
votes
0answers
75 views
0
votes
0answers
45 views

Code for solving numerically an integro-differential equation

First of all, I want to greet the community. This is my first question, but I hope I will be able to help answering others members questions, although I am quite new working with Mathematica. I would ...
0
votes
1answer
111 views

Finding solutions of polynomials system

Let $f_1,...,f_n$ be a set of polynomials in $x_1,...,x_n$ with rational coefficients. I need to check whether a system $$f_1=a_1,...,f_n=a_n$$ has a real solution for large enough count of points. ...
0
votes
2answers
148 views

find the real root

I have the following equation: \begin{equation} (y-1)^{b1} - C~~ y~~ \exp(a x)=0 \end{equation} where $a, b$ are real constants, $C$ may be a complex number. I need to find the real solution of the ...
0
votes
0answers
63 views

System of differential equations - solving for a constant

I will reformulate my question in the hopes it will be more intelligible. First, I defined the functions: ...
0
votes
0answers
52 views

Can't Solve a system of differential equations, Solve takes too long

My question is probably not really interesting but I really need help on this because I won't have access to a more powerful computer. So my model contains 7 equations : ...
0
votes
0answers
82 views

Solve function doesn't work

I have the following system of equations that I need to solve: ...
0
votes
0answers
44 views

Ideas for NDSolve?

I'm currently trying to find a numerical solution to a differential equation of the form: D[W[X], {X, 4}] ==(-(1/(delta + G - (G X)/L)^2) + 1/(delta + (G X)/L)^2) ...
0
votes
0answers
81 views

NDSolve producing an overdetermined system

I am trying to build the initial model for an electro-mechanical system that I will be running in a for-loop for various inputs and parameters. Currently, the code is as follows: ...
0
votes
0answers
120 views

What algorithms does NSolve use?

I've been using NSolve to find roots and now I've been wondering what underlying algorithm mathematica uses. It's probabaly similiar to ...
0
votes
0answers
58 views

Using NSolve in a function, selecting one indexed result and using it to plot another function containing a function containing the indexed result

I have a problem using the result pcvar[g] g e (0,1) in the plot cvar1. In the plot cvar I can use it. It must be somehow connected to clearing p in the definition of pcvar[g]. I am gratefull for any ...
0
votes
0answers
42 views

Verify “Type” of solution [duplicate]

I've written some Mathematica functions which allow the user to verify if a mathematical function has certain properties. What I'm basically doing is generating "random" functions in respect of ...
0
votes
0answers
56 views

Minimize solution to linear system with singular system matrix

I am trying to solve a time-dependent linear system with a singular system matrix, $A$, thus an infinite number of solutions, ${\bf x}$(t), exist that satisfy the linear system. The solution I am ...
0
votes
0answers
50 views

Solving an exponential inequality with parameters

Can I use Mathematica for solving the inequality given below? b^(x/2 - 3/2) - b^(ax) - 2c > 0 where b, a, c are the parameters. I want to find out for what ...
0
votes
0answers
51 views

Solving a single equation with multiple parameters

If I wanted to solve equations like Cos[x]^2 = A Cos[Bx + C] + D what function should I use? The Solve function seems to only solve for as many variables as there are equations. Please note that my ...
0
votes
0answers
39 views

FindRoot with units error: Message text not found

This is sort of embarrassing. I'm working on a document to extol the virtues of Mathematica, and I can't get it to solve a relatively simple system of equations involving units. In this code, when I ...
0
votes
1answer
159 views

Problem with Plot and ParametricNDSolve

This is my first question on this site, I hope it is written in an understandable way. Let's start. My aim is to plot a certain parametric region, with $x$ and $y$ coordinates given by the following ...
0
votes
0answers
50 views
0
votes
1answer
154 views

Minimize: How to work with specific numeric types

This is a question about the use of symbols in Minimize and how to persuade Mathematica to treat them in a specific way (as integers or rationals) that I have not ...
0
votes
0answers
48 views

FindRoot to find numerical solution of a given index

I want to find solutions of a system of multivariate nonlinear equations of a specific index (i.e., the no. of positive eigenvalues of the Jacobian evaluated at the solution). I know the FindRoot ...
0
votes
0answers
43 views

How to obtain all minima? [duplicate]

If you Solve an equation, you obtain all solutions. But If you NMinimize a function, you only get one minimum. The question ...
0
votes
0answers
126 views

Mapping the imaginary axis of the complex (s) plane

In this problem is very difficult to analyze the roots s. Firstly I thought that the problem is in precision, but I am not sure. The criterion which I want to obtain is that one of these roots has a ...
0
votes
1answer
234 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
votes
1answer
96 views

Numerical method for solving a polynomial equation

I am looking for a numerical solution of a equation which contains, in general, one polynomial equation with unknown variable x. I have tried Reduce, ...
0
votes
1answer
89 views

How to Solve/NSolve/Reduce this rationalized equation

In this problem I don't know why the system is not solvable. I have just one unknown K0. ...
0
votes
0answers
68 views

Solving for a variable within a definite integral using FindRoot

I want to solve for P in this equation: Integrate[1/((P/(M*V)) - r*g - c*A*(V^2)*p/(2 M)), {V, 0, 26.82}] = s , where all constants are given except P. I've ...
0
votes
0answers
61 views

How to solve an inequality

I am trying to solve the following inequality: Assuming[{R[k] >= 0, R[k + 1] = R[k] - 2^N Y, Y >= 0 && N >= 0}, Refine[Re[R[k + 1] >= 0]] I ...
0
votes
0answers
44 views

NSolve or Reduce for obtaining the results and connecting roots

Here I have one problem how to solve numerically equation for different values of one parameter x. I used just two digits because of length, but for x=0.57 I should have one real root and for others ...
0
votes
0answers
98 views

Boundary Condition Problem with Green's Function

My temperature distribution looks like: Mean wire temperature is : To[x_] := 2 c1 Cosh[x a1] + a2 And it is continuous at two points. In positive part: ...
0
votes
0answers
62 views

Solve gives solution with ComplexInfinity -> number

I am trying to solve a cumbersome equation using ...