# All Questions

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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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 ...
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### 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 ...
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### 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.: ...
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### 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: ...
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### 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 ...
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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 ...
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### 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 ...
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### 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 ...
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### 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' ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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