Tagged Questions

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

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Find all degenerate eigenvalues of a cubic equation

I have an equation that is cubic in w. The three solutions correspond to bands in a bandstructure, and are a function of wavevector ...
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Re-parameterizing sections of a Bézier curve into normal Cartesian functions [closed]

I have a table: ...
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solving system of non-homogeneous advection equation using mathematica?

This question is followed up from this question How to solve a certain coupled first order PDE system Here I consider the non-homogeneous advection system ...
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NSolve erroneously gives no solution to a polynomial system

I have a polynomial system with three equations in three unknowns, the maximum degree is 26. Two equations are symmetric, i.e. eq1(x,y,z)=eq2(y,x,z). If I search ...
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How to solve a certain coupled first order PDE system

I would like to find the solution $(U,V)\equiv (U(x,t),V(x,t))$ of the following system. \displaystyle\left\{\begin{array}{l} \frac{\partial U}{\partial t}+(a+b x)\frac{\partial ...
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Solve a transcendental equation in Mathemathica

I believe it is called a "transcendental equation", and I would like to find the best possible sollution. I tried to use Solve: ...
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Finding closest point to implicitly defined curve

I'm facing the following problem: Given an implicit curve given by $f(x,y)=0$ and an initial guess $(x_0,y_0)$ which is hopefully close to the curve, I want to find the point $(x,y)$ on the curve ...
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Solving a transcendental equation

I want to solve the a transcendental equation, e.g. NSolve[-(1-x)*Log[1-x] - x*Log[x] == 0.5, x] Mathematica is not able to solve, wheres WolframAlpha -- is able ...
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Reduce Inequality

How can I reduce the inequality in terms of modulus of alpha. ...
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How to solve a nonlinear overdetermined system of equations

i'm trying to solve a nonlinear overdetermined system of equations (124 equations, 123 variables) i tried this procedure (newton raphson) ...
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Is there any way to get an exact solution a system of non-linear equations? The system I would like to solve is: $\quad \quad \begin{eqnarray} h_{1}x_{1}=c_{1}\\ h_{2}x_{2}=c_{2}\\ ... 1answer 93 views How can I solve an equation independent of a variable? [duplicate] Let's say I have the equation $$ax + b = 0$$ and I'd like to find a solution that doesn't depend on$x$, so here the solution is obviously$a=b=0$. I could solve this using ... 1answer 168 views How to properly interpret a seemingly contradictory result in Mathematica? I have a problem with interpreting the results of my notebook outputs. It is important that I do not err with the interpretation. Here is the full input: ... 0answers 55 views Problem with plotting a function that calls FindRoot I am having difficulties in plotting the solution of FindRoot to solve 4 variables. I defined a function and then tried tp plot it, but got an error message ... 2answers 105 views Solve returns empty list / running forever Update: I made a mistake before and corrected the sign in code below in case people wonder what some comments mean. Thank you for those who answered. But I should have said that this is only part of ... 2answers 107 views Why does Mathematica not evaluate the difference recurrence using RSolve or RecurrenceTable? Mathematica does not evaluate the following recurrence of two variables using RSolve and only echoes the input: ... 1answer 113 views How to find zeros of 16th degree polynomial with coefficients which contain one symbolic parameter? I'm trying to find eigenvalues of matrix which is 16x16. Here is a part of matrix: ... 0answers 61 views Inverse Superposition There are 4 tables that, I have written them as bellow: (m, n, s, and r are orthogonal basis. r.r=n.n=m.m=s.s=1, and m.n=n.r=...=0). a's, b's, c's and d's are coefficients and are numeric values. ... 2answers 108 views Solve[ ] doesn't work with transcendental equations How to solve x^5-sinx=0 in mathematica? I try in this way: Solve[x^5 - Sin[x] == 0, x],but t doesn't work. 1answer 150 views How can I find all solutions of a complicated expression in a desired interval with Mathematica? I have an expression which is a combination of Bessel functions: ... 3answers 110 views Problems with finding the real solutions of equation I am trying to find real solutions of equation using Mathematica 8.0 but there is some problem I don't know how to explain. For example, for the input ... 1answer 40 views Unexpected ReplaceAll behavior with NSolve I ran into some unexpected behavior using ReplaceAll with an equation of motion using NSolve (or Solve, also). First solving for the initial velocity v0: ... 6answers 542 views Finding where two parametric paths cross? I have been looking through other parametric equations questions and am still unsure where to start with this one. I am given two functions: ... 2answers 83 views Switching between solutions of a fourth order polynomial I am plotting the roots of a fourth-order polynomial as a function of some parameter$r$with the following code: ... 0answers 72 views Finding values of a variable fitting a function and minimizing a list of expressions I am trying to implement bootstrapping (https://en.wikipedia.org/wiki/Bootstrapping_(finance)) of CDS curve. To implement it I am trying to minimize a series of expressions so that each expression is ... 0answers 33 views why is NSolve giving {y,x} in place of {x,y}? [duplicate] Why is NSolve giving an inverse set of solution? Is it a problem with my computer only? ... 1answer 127 views How to Solve[] for rational constants? I am trying to solve a system equations for rational, constant coefficients: ... 1answer 65 views Find a minimum value which satisfies an equation I have to find a minimum value of "a" which makes x=-a+b+c, y=-a+b+c^2 positive where a>1, 0 ... 1answer 105 views Inaccurate answer for a system of equations When I solve the following system of 6 equations by NSolve, it gives me an answer set; however this answer won't make the 2nd equation equal to zero (i.e. when I put the answers into ... 3answers 158 views How to find the solutions to$a+b+c+d=60\$?
How can I find all the solutions to: $$a+b+c+d=60\quad (0\leq a,b,c,d\leq 30,\; a,b,c,d\in\mathbb N)$$ I've tried to use Solve[], but it says that there are more ...