Linked Questions

0 votes
1 answer
67 views

A specific usage of "Solve" function [duplicate]

It is something from Simplifying polynomials with conditions on variables, that intend to minimize the number of variables. The problem is the usage of ``Solve". I know how to solve equations, ...
InFei's user avatar
  • 115
214 votes
26 answers
17k views

What are some useful, undocumented Mathematica functions?

There have already been some questions about some undocumented functionality in Mathematica. Such as (please add to these lists!) How can one find undocumented options or option values in Mathematica?...
11 votes
4 answers
7k views

How to solve an overdetermined system in Mathematica

I would like to understand the reasons and find a way to avoid such behaviour of the Solve function in Mathematica 8. ...
Nikolay Rys's user avatar
18 votes
2 answers
2k views

Behavior of Reduce with variables as domain

When using Reduce, I accidentally put a set of variables as the domain. To my surprise, it not only seems that Reduce expects ...
Tyson Williams's user avatar
4 votes
2 answers
383 views

Rewriting algebraic expressions as combinations of other expressions

I would like to write x^5 + 1/x^5 in terms of x^2 + 1/x^2, x^3 + 1/x^3 and ...
Real Noob's user avatar
  • 219
1 vote
1 answer
472 views

How to speed or help Solve[] when it is stuck?

The code below generates a system of equations that I need to Solve[] for {c[5], c[6], c[7], c[8]} in terms of {c[1], c[2], c[3], c[4]}. ...
Jerry Guern's user avatar
  • 4,632
4 votes
2 answers
164 views

Arrange a system of differential equations to standard state-space equation form

I want to model an electrical circuit in the form of state-space equations, and I want to use Mathematica to solve the final equations, the circuit equations (from Kirchhoff's law) are shown below, ...
Nihan Tong's user avatar
1 vote
1 answer
109 views

Expression substitution

I konw: $$ a_0=\frac{4 \pi \epsilon_0 \hbar^2}{m_e e^2} $$ and $$ \alpha = \frac{m_{\mathrm{e}}^2 e^4}{18 \pi^3 \epsilon_0^2 \hbar^4} $$ So we can use $a_0$ for $\alpha$,like this: $$ \alpha=\frac{m_{\...
我心永恒's user avatar
  • 1,572
4 votes
2 answers
154 views

Simple symbolic parametric differential equations

I'm relearning Mathematica after a long time away, and trying to remember how to do some things best. At this point, I'm trying to evaluate $\frac{dy}{dx}$, given: $$ \begin{align} y&=\frac{3}{t}\...
Piquan's user avatar
  • 476
1 vote
1 answer
199 views

How to help Mathematica Solve simple substitution equation?

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user avatar
0 votes
2 answers
174 views

solve nonlinear differential equations for some variables [closed]

I have a few nonlinear differential equations and some variables that I need them to be eliminated when I am calculating differential equations based on other 3 variables, but I can just get an answer ...
F R's user avatar
  • 159
1 vote
2 answers
56 views

Solving simuntaneous equations with elimination of a variable [closed]

I have the following relations: Dc == k*t0^2 Dp == k*t1^2 I know that I can do the following: $\qquad \frac{D_c}{k\space t_0^2}==1 \quad \frac{D_p}{k\space t_1^...
Quark Soup's user avatar
  • 1,610