All Questions

335 views

How can I speed up this code with multiple sum？

There are 4 variables in this multiple sum, therefore it may take a long time. I have run this program for 12 hours, but no result untill now. I want to know how to speed up this code. Any help or ...
185 views

Exhaustive examples of variable replacement due to nested scoping constructs

Consider the following examples, where I have replaced dollar signs in the output by a D. ...
127 views

Creating Do loop that cycles back to earlier values

I need to create a Do loop that distributes letters in a list of lists. I also need to be able to cycle back through to the beginning of the list. For example, I ...
105 views

149 views

Edit Automatic PlotRange

if I have a plot let us say Plot[x^2 - 5 x - 10, {x, 0, 8}] I want o check if there is a way to know the automatic plot range and to add or subtract from that ...
193 views

Strange behavior of Reduce with a cubic equation

This equation: $(\frac{-a}{x})^2=\sqrt{\frac{1}{x}}$ at $a > 0$ and $x > 0$ has a clear solution $x=a^{4/3}$, doesn't it? However, ...
53 views

Quoting definition explicitly

I'm trying to quote a definition using DownValues, OwnValues, etc. Everything seems to be fine, except for temporary symbols' ...
199 views

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197 views

How to correct this, f[a_] := FindRoot[eq == 0, {x, 0.5}], where eq contains a parameter $a$, without using eq[a]`?

I want to solve an equation with a parameter $a$, and define the result as a function of $a$. It is something like this: ...
588 views

Reversing Autocorrect, aka how to find the word that was supposed to be there

When I receive messages from people using their smartphones I usually see typos and, worst, typos corrected by Autocorrect. Now, I receive messages in English, which is not my first language. I can ...
151 views

FullSimplify inconsistent

I'm having problems using FullSimplify to simplify a differential equation. The expression is simplifying just as I would like when I express a variable ...
348 views

Plotting a Spericon and Bipyramid with 100 faces

I would like to plot convex polyhedron with 100 faces, which could be used as a die. My first attempt was asking for Conway's Hecatohedron. Unfortunatly, it can not be used as a die. Now there are ...
139 views

how can I make a control for my vector equation in my simulation?

I'm trying to build a control selector or menu for equations to put into my curvature simulations. However all the code I've tried hasn't worked.Does anyone know how I could make a control selector or ...
173 views

Why does GraphicsGrid rescale 3d plots?

In the documentation for GraphicsGrid, it says By default, GraphicsGrid will display graphics at their specified sizes So why does it rescale the 3d plots ...
68 views

DownValues Type Access and Timing

I definitely use so much DownValues structure for some many applications like to replace some common structures in a some way. It seems that DownValues is so fast for access, and set. My question is ...
50 views

Correctly substituting a matrix into a scalar equation [duplicate]

I am having trouble correctly substituting a matrix into an (originally) scalar equation. For example: A = {{3, 1}, {1, 2}} cp = CharacteristicPolynomial[A, x] ...
215 views

Plotting John Conway's Hecatohedron

John Conway has given an explanation how a regular Hecatohedron (polyhedron with 100 faces) looks like: http://www.ics.uci.edu/~eppstein/junkyard/hecatohedron.html Conway explains: Here's a ...
40 views

How to generate Koch curve in mathematica [duplicate]

How is done in Mathematica to generate the curve? Exists in the fractal geometry Koch curve, consisting of partitioning a line segment of lngitud 1 in three equal parts, by removing the central part ...