All Questions

I have an expression of the form: expr=x+y+n+Sin[n]+n^2 I would like to replace each of the variables n with a different ...

How can I derive analytically or compute numerically the solution to following differential equation $$ dy/dt = y\cdot X\cdot (y\cdot X - g(y,X))\cdot X $$ where X is a random variable (e.g. from a ...

I have a table form as: table = {{a, 6}, {b, ff}, {c, 2}} I want to associate the first element of each pair from the table to the second element of the pair as ...

Where can I find examples devoted to extracting information from functions that returns nested structures with DefineDLLFunction in Mathematica? The only example I ...

I will appreciate if anyone can give me an hint about freepascal and mathematica mathlink communication. I'd like to build a Form using Lazarus/freepascal that call mathkernel. I'm trying to move ...

This is Right. NestWhile[Log, 100, # > 1 &] {100} //. {x_} /; x > 1 :> {Log[x]} 100. //. x_ /; x > 1 :> Log[x] This is wrong,why? ...

I have a problem with my Mathematica 7.0 When I write: Derivative[x^2, x] Mathematica returns as result : Derivative[x^2, x] ...

This is a continuation of: Why do certain fractional values in TriangleWave not evaluate? The analysis by R.M and rasher revealed that problem to reduce to the behavior of: ...

I'm attempting to add $MachineEpsilon to numbers I am pulling from the domains of 3 interpolating functions. I pulled 3 numbers, and for one of these numbers adding ...

I'm trying to assign random image files that undergo rescaling to a list of variable names. The images I'm trying to assign are the result of mapping the ImageResize function of two arguments to the ...

Bug introduced in 8.0 or earlier and persisting through 11.0.1 or later While answering another question I discovered that TriangleWave does not automatically ...

I have a Manipulate where a portion of the calculation that ends up displayed is dependent on a subset of the Manipulate control ...

I want to plot values of a table for example: table = {0.456, 0.7899, 1.3456, 9.8908} But I want to Plot points (x,y) like: ...

Shorthand syntax provides an alternate way to apply functions and, in many cases, improves readability. A simple example would be ...

I would like to show that the following (and other similar formulae) tends to zero. Limit[Sum[(2*E*n)^w/(w^(n/2+w)), {w,2,n}],n->Infinity] What's the right ...

Adding a textfield to the function that I implemented to represent the tangent or derivative of a function, but I've added so mark errors. ...

Suppose that I have the following list, called list. list contains elements X, ...

How can I get binomial coefficients in expansion of $(n x+i) (1+i x)^n+(n x-i) (1-i x)^n$, where $i=\sqrt{-1}$ and $n$ is an integer. I have no idea how to coax Mathematica to do something remotely ...

I need your help with making a slider invisible and visible in a Manipulate. Here is my code: ...

I'm trying to use Mathematica to make some work on binary data, and I'm missing something. Consider the string "111". I want to flip the last bit to become ...

I was wondering if I can toggle the "CellOpen" state from a cell (or bunch of cells) from another cell. i.e. I am imagining having a manipulate command along the lines of: ...

I have a function $O_{2}$ with boundary conditions $O_{2}(r_{o}) = p_{o} $ and $O_{2}(g) = O_{2}'(g) = 0$. I plot it using the solver code below; ...

I am trying to find out partial products going up in prime steps for Euler's product formula $$\prod_{p} \frac{1}{1-p^{-s}}$$ Trying things like ...

From my understanding about Linear Interpolation especially of that of Newton's Divided Difference Polynomial, we could get the value of F(x) from the given set of ...

Please help - I'm really struggling to understand why this evaluates with errors. ...

Here is a function that calculates the probability of randomly landing on a Fibonacci number not greater than $n$: ...

Right click on an output image, choose magnification. There are 25%, 50%, 100% etc. But how can I set to 75%?

I'm interested in using Solve[] to find the centre point of rotation (as an $x,y,z$ coordinate point) and axis of rotation (as a vector) from a ...

I have data generated from two functions given below. How can I go about finding a fit of the form: y'[x] == -(a + b/(c + d y[x] + e F[x] )) where a,b,c,d,e are ...

I create three random images: i1 = Image[RandomReal[1, {8, 12, 3}]]; i2 = Image[RandomReal[1, {8, 12, 3}]]; i3 = Image[RandomReal[1, {8, 12, 3}]]; I can scale a ...

What is wrong with the following code? CirclePlus := SparseArray[Band[{1, 1}] -> {##}] & a_ ⊕ b_ := CirclePlus[a, b] SetDelayed::write: Tag Function in (...

I need to solve an polynimial equation, but when i try to use Solve or NSolve in mathematica, its cant find the solution in appropriate time (i interrupted calculation after 5 hour left). The ...

How may I make n and k in terms of x and y in this ...

I have a Variable assigned a value, say ImportantDocuments=1 How do I make N["ImportantDocuments"] evaluate to be 1 instead of ImportantDocuments I found that N[ToExpression["...

I want to numerically solve the heat equation. To do so I wrote a program in C++ - It is a BVP $(\alpha T +\kappa \frac{\partial T}{\partial r}=f(t))$, where $f(t)$ is an arbitrary function, whose ...

I have a complex variable, and I'm trying to multiply it by its Conjugate[], which should give me a real number. So, I'm currently doing: ...

Edited to fix an inconsistency in the given example data format. I'm trying to write a simple function to load in a csv list of names which is formatted as "Lastname Firstname Initial " and ...

How Can we use PixelValue with pixel indices?

If I execute: In[1] := x = x Out[1] = x and then I evaluate the symbol x: ...

I have a program that needs to be done like this: ParametricPlot[ equation, If[x < 1, {x, 0, t}, {x, t, 2}]] But Mathematica didn't seem to recognize the ...

Bug introduced in 6.0 and fixed in 10.0 I want to find the integer values $k$ so that D[f[x], x] has integer solutions. I tried ...

I want to compose a string that contains newlines, so I tried the following: ...

I have currently used "Save Selection As" after highlighting the graph and legend and then saved it as a PNG file, but the quality isn't brilliant. I am using TeXworks on Windows 7. The "Copy As LaTeX"...

I noticed that when I enter full-screen mode in Mathematica 9 (F12 for Windows) using a magnification of 125% (or any other number higher than 100%) there is a horizontal scroll bar at the bottom of ...

I wish to get a view plots from Mathematica trial version into a TeX editor, but cannot seem to do it (unless I print the screen and crop the image which leads to bad quality). Is there a way in which ...

I have the following data which is postulated to have contributions from two different sources .....as can be seen from the confidence band, many points are out of the band. Question: How can I ...

I'm confused by why the following doesn't work. I'm trying to numerically minimize a function that has an If statement in its definition, as follows: ...

In the Mathematica front-end, symbols that have been defined are colored black and symbols with no definition associated are colored blue. This is useful to prevent spelling mistakes. Also, defined ...

I have some larger square, Hermitian matrices, M, (dimension 20, say, much more than 4) with 2 independent variables, call them x and y. I can plot the eigenvalues as functions of x and y with: <...

I have a lot of files in a folder that needs to be process through a function that I have written in Mathematica. I need help writing a code that would process all the files automatically. ...