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1answer
73 views

(Row?) reduction of a system of equations

For a mathematical problem I am trying to solve, I have (say) $(N+1)$ inhomogeneous linear equations in $M$ variables of the form $$\sum_{a=1}^{M}c_{i a}p_{a} = \xi_{i} \quad \text{ where } i=1,\...
0
votes
1answer
31 views

Selecting solutions that evaluate to positive

How to extract symbolic outputs of Solve that evaluate to positive at given values of parameters? For example, if ...
0
votes
0answers
31 views

How to compute a system of ordinary differential equations with initial condictions over a continuous range

I have some questions about Mathematica programming and would appreciate if you could help me. I want to solve a system of ordinary differential equations \ [Mu] '[t] and \ [Lambda]' [t] and each ...
2
votes
1answer
75 views

Numerically solve system of 64 equations with 64 variables in matrix form

I have 2 matrix $A$ and $B$ both of size 16x16. Most of the values $A_{i,j}$ and $B_{i,j}$ for the same couple $(i,j)$ are equal to 0. The remaining ones are a positive floating number for $A$ and a ...
0
votes
2answers
70 views

Matrix equation solving

I am new to Mathematica and I try to apply the solution given to this problem. So I have: $$A = \begin{pmatrix}50 & 3 & 10 & 2\\\ 3 & 60 & 7 & 1\\\ 10 & 7 & 55 & 4\...
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1answer
35 views

diagonalisation of systems of symbolic equations from two cross products

A description of what I'm attempting: Given a generic vector $\vec{r}$ and a point in space $D$, I want to build a reference frame centred in $\vec{r}= (x,y,z)$, with one axis directed along the ...
0
votes
0answers
44 views

Solving a system of linear equations with complex unknown

I am trying to solve the system of equations which is given by $ABA^*=-B$, where A is $2\times2$ matrix, $A^*$ is a conjugate transpose of $A$ and $B$ is a $2 \times 2$ unitary matrix. Entries of both ...
1
vote
1answer
55 views

Interpreting the solution for a nonlinear system in a matrix form

I have an issue of how to interpret the solution of the following nonlinear system in a matrix: $F=PX^{-1}AX+wL$ where $w>0$ is a scalar, $F=(F_1,F_2)$, $P=(P_1,P_2)$, and $L=(L_1,L_2)$ are all a ...
0
votes
1answer
36 views

Conditions to make unitary a given matrix

Suppose I have some symmetric matrix W = {{c[1, 1], c[1, 2], c[1, 3]}, {c[1, 2], c[2, 2],c[2, 3]}, {c[1, 3], c[2, 3], c[3, 3]}}; where the c's are complex and I ...
1
vote
1answer
172 views

How do you avoid Null in matrix? [closed]

The following matrix equation is a Lyapunov equation, $$ mA.x+ x.mA^T=-mC,$$ the matrix $mA$ is given by $$ ...
1
vote
2answers
39 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 ...
2
votes
2answers
79 views

Solving for three parameters from a matrix equation and storing them in separate variables

Say I have a matrix $$ Z=\begin{pmatrix}-\frac{1}{\sqrt 2} & \frac{i}{\sqrt 2} \\ \frac{i}{\sqrt 2} & -\frac{1}{\sqrt 2} \end{pmatrix} $$ and another matrix $$ U(\theta, \phi, \lambda) = ...
0
votes
1answer
24 views

Problem with solving a system of equations based on a matrix

I am trying to solve a system of equations based on a matrix in order to find the "stationary" matrix. the code I've written should break the matrix down into a system of equations such that some ...
4
votes
2answers
487 views

`FindRoot [ ]`::jsing: Encountered a singular Jacobian at a point…WHY

I have a large system of linear and nonlinear equations. I know that the system is not singular at the point given because I calculated the Jacobian and evaluated it at a given point. The resulting ...
0
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0answers
47 views

How can I speed up my code finding the parameter which yields zero determinant for increasingly larger matrices?

I build a square matrix with matrix elements dependent on the parameter x. I need to find all values of x within a reasonable ...
1
vote
1answer
22 views

How to define a function, that generates matrix of variables, which can be later used in Reduce?

My goal is to generate matrices, on which I will put different constraints in Reduce funcion, e.g.: ...
2
votes
1answer
50 views

Reduce returns false on equation solvable by LInearSolve [closed]

I was looking for general solutions of an equation I already solved for specific values with LinearSolve, but using Reduce returned False. Here's the code: ...
0
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0answers
64 views

Calculating forces on a truss

I need to find certain forces of the truss shown above, and I am asked to calculate the forces with a matrix. The given values are ...
0
votes
1answer
64 views

Finding Steady States that Meet Additional Constraints

I've written a function that returns the steady state given a regular, column-stochastic matrix. I want to use it to solve a larger problem, finding steady states that satisfy certain conditions. The ...
0
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0answers
116 views

Why can't Nsolve find the solutions for my equations?

I have a problem using NSolve in my Mathematica code. In my Code NSolve should find a value for qw, but it won't. The strange ...
0
votes
0answers
55 views

The determinant of the matrix is very big, and solving becomes very difficult

I have a matrix of R1 of dimension 14 cross 14. I am trying to take the determinant, which happened to be the function of x and trying to find the roots of the determinant equation. But the det ...
0
votes
1answer
69 views

What is going wrong when I try to solve a simple linear equation? [closed]

I'm trying to understand how does the LinearSolve function works. I'm trying it out like this: A' ...
0
votes
1answer
28 views

Solving an equation involving a determinant (including spherical recursive functions)does not compute

I'm trying to solve this matrix to get a resulting function that depends on the variable Q (or if impossible, H3). When I try to to that I get two results: if I try to solve for Q, it doesn't show ...
1
vote
1answer
39 views

Find Transformation Matrix for Vectors of Functions, and Restrict Results of Solve Function

I have two vectors v,w which have a rather simple linear transformation A.v=w. My goal is to obtain ...
4
votes
1answer
300 views

Solving the eigenvalue problem for a double well potential using a 1D particle in a box as a basis set

My first question is how would I go about getting the 1D particle in a box eigenfunctions using matrix techniques and how would I use the particle in a box eigenfunctions as a basis set for the ...
0
votes
0answers
38 views

Find a matrix that are unitarily equal to the given matrix

I have four $5\times 5$ matrices, $P_i, Q_i$ ($i=1, 2$) as follows: $P_1=\begin{pmatrix} 1 & 0 & 0 & 0 & 0 \\ 0 & 1 & 0 & 0 & 0 \\ 0 & 0 & 0 & 0 & -...
0
votes
1answer
101 views

Finding all the solutions of some matrix equations

I am trying to find all possible solutions to the following: A = ( { {a11, a12}, {a21, a22} } ); B = ( { {b11, b12}, {b21, b22} } ); A.A <...
0
votes
0answers
41 views

Solving a system of linear equations in Mathematica regarding the errors of different methods

I have a system of equations, i.e. 0.62243x + 0.51824y = 0.70524 0.71497x + 0.59496y = 0.80996 I have 3 ways to solve this system (there are more but I am ...
1
vote
2answers
57 views

Build matrix from smaller matrices or rearange list of lists

Start with the fact that I am a new user of Mathematica, and this is my problem: I have a complex simbolic matrix A (rectangular, 14x14), and I want to build a matrix from its imagenary and real ...
1
vote
0answers
58 views

Find value of variable for unique, infinite and no solutions in equation system

How do i find which values of a variable in a equations system that gives unique, infinite and no solutions? My example: \begin{align*} ax + y + az &= 2 \\ x + ay + z &= 2 \\ x + ...
1
vote
0answers
66 views

Find parameter which solves a 9-by-9 homogeneous system of linear equations, NSolve gives some incorrect answers

I have a set of 9 linear homogeneous simultaneous equations which depend on 2 parameters, p and x. For a chosen value of p, I aim to calculate the smallest 3 values of x which satisfy the simultaneous ...
2
votes
1answer
140 views
2
votes
1answer
62 views

Getting error message from NSolve

I'm trying to solve for coefficients $k1$, $k2$, $k3$, $k4$ in the following equation: $\det\left(\,\begin{bmatrix}k1+k2 & -k2 & 0\\-k2 & k2+k3 & -k3 \\ 0 & -k3 & k3+k4\end{...
0
votes
1answer
124 views

NSolve/FindRoot matrix equation and conditions

I have an eigenvalue (vector) problem (please see the theory, maybe I missed something in the post or did not understand Eqs (3.5.24) ) how to obtain two unknown matrices (36 unknowns) to satisfy ...
0
votes
0answers
34 views

To find the Null Space of a matrix which is inside the module

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7
votes
4answers
314 views

Find the order $m$ of a matrix ${\bf A}$ such that ${\bf A}^m= {\bf 1}$

I have a square matrix ${\bf A}$ defined over the field $\mathbb Z_2$ and I want to find its order such that ${\bf A}^m=1$. I tried using ...
10
votes
1answer
373 views

What does LinearSolve Preconditioner do?

I have looked at a few places in order to find an answer to my question - specifically, I have looked at this old Mathematica documentation page, at the Preconditioner option for NDSolve, as explained ...
0
votes
3answers
287 views

Solve matrix equation

I have this 4x4 Matrix to which I apply the Solve function: A = FullSimplify[Solve[Aux == 0, {r10, r20, r30}]] Essentialy, it ...
2
votes
1answer
76 views

General solution of linear system of equations

How can I solve a linear system of equations and get the general solution? Let $A$ be $m \times n$ and $b \in C(A)$. How do I get the general solution of $Ax=b$? Example: Let $A= \begin{bmatrix}1&...
2
votes
0answers
35 views

Search the full group $G$ based on the partial list of its matrix representations

Suppose I have a list of matrices that may represent the partial list of the full group $G$. And here are the given set of 7 matrix elements. $$e =\begin{pmatrix} 1 & 0 \\ 0 & 1 \end{...
0
votes
0answers
84 views

System of unknown matrices

I am very new to Mathematica. I am attempting to solve a system of equations with 4 unknown matrices (B, C, D and S). B, D and S are symmetric. This is what I have: ...
3
votes
3answers
149 views

Solution for coupled equations with trigonometric functions

Suppose we have set of matrix equations, for this case lets consider a 2x2 set. The equations are: ...
0
votes
1answer
112 views

Where do two bicubic-interpolated surfaces intersect a plane?

I have two surfaces, $p_a$ and $p_b$, described by two matrices. I want to find out if both surfaces intersect with the planes $q_a$ and $q_b$ respectively for any pair of x and y coordinates. To do ...
1
vote
1answer
51 views

Calculations with vectors and matrices

Given the following equation. How can I run this in mathematica and get the same result? I naively tried it like this, with: ...
2
votes
2answers
94 views

How to solve for this matrix?

I have a mapping $f:R^3\rightarrow R^3$ such that: $$x_1=(1+\eta)X_1$$ $$x_2=(1+\gamma)X_2$$ $$x_3=(1+\gamma)X_3$$ and I have to obtain the transformation matrix $\varepsilon$ corresponding to this ...
2
votes
1answer
107 views

How do I set guess constraints for a solution of a linear system of equation?

Let's say I have a linear system of equations $$ Ax = \biggl( \begin{matrix} 1 & 2\\ 0 &1\\ \end{matrix} \biggr) \biggl(\begin{matrix} x_1 \\ x_2 \end{matrix} \biggr) = \biggl( \begin{matrix} ...
1
vote
1answer
210 views

How can I solve my system of linear equations? [closed]

I have a pretty easy problem where I have 6 equations and 6 unknown of the form m*x = 0, where m is a 6x6 matrix and x is a vector of length 6 with the 6 unknown variables. I'm looking for a ...
2
votes
1answer
73 views

Matrix Solve for a particular form

Suppose that we have two matrices $\mathbf A$ and $\mathbf B$ which are known to us and both of them are square matrices of the same dimensions. Now we want to find a square matrix $\mathbf C$ that ...
2
votes
1answer
127 views

Storing Multiple solutions from Solve as rows of a matrix

I am trying to find all the solutions to a Diophantine equation (only integer valued solutions) using Solve[], however there are multiple and even many solutions sometimes. How can I store these ...
0
votes
1answer
528 views

Find the non trivial solution of a matrix

I have the following matrix: ...