# All Questions

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### Calculate the expectation of psi(x) with a gamma density x∼Gamma(α,β )

Suppose I have a Gamma distributed random Variable x∼Gamma(α,β). Now I want to calculate the following expectation values (integrals): E[psi(x)] with psi(x) being the digamma function Many thanks ...
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### Loop and list all p-values (percentage and not histogram)

I have the following Mathematica code (see below). It currently provides a histogram as the solution. Instead of a histogram I want to count the number of times the p-value calculated surpasses a ...
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I have the following animated parametric curve where the gap looks like it's rotating in the counterclockwise direction. ...
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### Inverse Exponential and Logarithmic Functions

If I define f[x_]:= Exp[x] g[x_]:= Log[x] then both f[g[x]] g[f[x]] should equal to ...
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### Access API arguments

If I am deploying FormFunction CloudDeploy@FormFunction["name"-> "String",doSomethingWithName[#name]&,"PNG"] is it possible to access a parameters ...
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### Moving certain variables to one side of the equation

I am having trouble moving certain variables from one side of the equation to the other. For example, if i want to solve for x1: ...
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### how to solve impulsive differential equation in mathematica [on hold]

this is my system, i need help to solve this.i want to know that how to put impulse condition in Solve command
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### I need to solve the Mathieu equation: $y''(x)+(a−2q \cos(2x))y(x)=0$

I want to know what will be the boundary conditions? For integer order and $\pi$ periodicity? How I can find solution of equation?
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### Label points the right way in a ContourPlot

I need desperately your help. I have the following code. My problem is that there is an error (you see it in the picture) and I can't find. Then Mathematica gives me for the global Min two wrong ...
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### How to format the background color of page footers and headers

I have created a StyleSheet by modifying a copy of Default.nb. The StyleSheet applies a dark grey background at the Notebook level. However, when I export to PDF and exam Print Preview (although PDF ...
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### Is there a way to control which special forms Normal converts?

Normal documentation reads: Normal[expr] converts expr to a normal expression, from a variety of special forms. But is there a way to control which special ...
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### Showing Boolean combinations with ParametricPlot3D

If $A,B$ are $\mathbb R^2$ surfaces, Show[A,B] shows the union set, say as {A+B} or as ${A \cup}B$. How are differences {A-B}, {B-A} shown by a command? E.g., am curious about a cylinder ...
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### Strange bug involving a list, “Objects of unequal length” [on hold]

Please let me know if I should attach all of the code. I have only decided to attach the problem code to make it easier to read. So hopefully it is enough. sortedTally is a list generated from ...
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Consider: ...
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### Manipulate on Mathematica Online

I am absolutely new to Mathematica Online. Using Mathematica 10.1.0.0 on my MacBook Pro (OS X 10.10.3), the following code works perfectly. ...
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### 3D FEM with holes

I'm trying to create a finite element mesh with some spherical holes. To my mind the behavior is erratic but generally fails. I'm using MMA 10.0.2. In the following 3 different sets of holes are ...
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### How do I solve and graph this coupled PDE?

How can I solve and graph v1 versus t and v2 versus t for a given x? Let A = 3, p = 2, B = 4. At t = 0, v1 = 2, v2 = 2. For the graph the range of t is [0,60].
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### Different result when using 0.5 or the fraction 1/2 (negative base exponential) [on hold]

I think this code speaks for itself In[1]:= (-3)^(1/2) Out[1]= I Sqrt[3] In[2]:= (-3)^(0.5) Out[2]= 1.06058*10^-16 + 1.73205 I
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### Assymptotically Solving ODE with free parameters

I have a first order ODE, $F(y[x], y'[x], A, B) = 0$. I want to solve this numerically (with the boundary value $y[1] = i$ ) but also with the following requirements: A and B are free parameters which ...
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### Extract x-values from InterpolatingFunction object? [duplicate]

Ok, So I have a numerical solution to a differential equation, and I am trying to get the data points out from it. So far, I have only been able to get the y-values with the following code: ...
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### List of prime powers

I have a list of not necessarily distinct prime powers. For example: {2,3,4,25,2,3}. I want to combine (multiply) the highest prime powers for each prime. In this case 25*3*4 = 300 since 25 is the ...
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### Deploy API which calculates matrix operations

Is it possible to deploy to cloud a matrix entry form and when submit button would be clicked and then an operation using entered matrix as argument would be executed? So far I am able to deploy ...
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### Pattern matching list of elements with different heads

I have a function, which I want to accept only a list of kind of elements belonging to a group. The task comes down to finding an elegant pattern suitable for easy to read function prototype. As an ...
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### Arbitrary precision calculation with NDSolve

I am trying to solve a BVP using shooting method. For this problem I am guessing one initial condition and also a parameter of a ODE. This is why I am not using Mathematica's in built shooting solver. ...
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### Alt drag does not work properly

When a graphics is displayed, right clicking will bring up the Get Coordinates tool. To select a rectangular region, you can do it manually by selecting the two corners and Alt+C will copy these two ...
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### Map function with a counter

How can we embed a counter in the Map function? Consider a data set such as data = {{a, b, c, d}, {e, f}, {g, h, i}}. The ...
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### FindFit set of {x,y} data [on hold]

I have been trying to find fit for data I have in form {x,y}. Here are my data: ...
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### One point following another moving in a straight line? [migrated]

There is a plane with two points on it, let's say A and B. A starts at an arbitrary constant point, let's say (0, 0), and B at a point that needs to be tested, which we'll call (c, d). A moves ...
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### Efficiently find all connected subgraphs

Is there a way to generate all the connected subgraphs of a graph in mathematica without going through all the subsets of the nodes and checking if the subgraph is connected (which will be ...
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### Multidimensional arbitrary precision spline interpolation on the grid

This question is a generalization of the previous one for multiple dimensions. In the answer to that question an implementation for the clamped spline interpolation for 1D case and arbitrary degree of ...
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### Why is ListPlot so slow here?

While examining How can I monitor the progress of a Plot? I was surprised to discover that in some cases ListPlot in version 10.0 and 10.1 is orders of magnitude ...
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### “Input has Generated an intersecting boundary” Problem with ToBoundaryMesh function

I have a list of points from which I am trying to generate a mesh: ...
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### Frequency of punctuation characters used in Mathematica languages

I would like to determine the computer language character frequency in Mathematica code. I want to remap my keyboard to the most used character such as [], {}, -, +. There are the frequency of ...
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### memory management in Mathematica

Unlike using Unprotect[In,Out]; Clear[In,Out]; Protect[In,Out]; to clean the occupied memory of the whole notebook, I want to clean the memory dynamically and ...
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### How to create protected single-file stand-alone CDF applications

After hours of work trying to understand how much protection I can get when creating stand-alone CDF applications I have come to the decision that the best protection to my work is provided by ...
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### NIntegrate fails to converge around a value out of integration range

This is the function that I am trying to integrate, I have interpolated it for best results (would rather not): There is a 'singularity' around 0, but I get the warnings and bad results even when ...
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### Numerically solving Helmholtz equation in 3D for arbitrary shapes

Context While studying manifold Learning I got interested in finding the eigenvectors of the Laplacian. (also in connection to this problem of solving the heat equation) Following this and that ...
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There is an interesting algorithm called contrast enhanced adaptive histogram equalization that does histogram equalization on small segments of an image (and then pastes them back together). I know ...
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### Interpolation curve [on hold]

I have a complicated parametric curve which takes too long to integrate, therefore I want to sample points and interpolate to speed up calculations. The curve is: ...
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### Parenthesize what I have highlighted

I want to highlight a piece of equation, click a button and have that part taken into parentheses.
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### Constructing a function for expanding general $n$ products

I have the following quantum mechanically motivated product: $\langle0\vert(A_1b_1 + A_2b_2 + A_3b_3)(B_1b_1 + B_2b_2 + B_3b_3)(C_1b_1 + C_2b_2 + C_3b_3)$, where $b_i$ is an annihilation operator ...
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### Piecewise and Opacity

I have the following Plot : ...
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I have some data from wikipedia. ...
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### How to make static labled tables? [on hold]

How can I create something like: ________________ |_Prop1__|_Prop2_| Image1 | ... | ... | ------------------- Image2 |_...____|_...___| ...
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### Insert points in a ContourPlot [duplicate]

This is my code ...
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### How can I avoid to define public all methods in a package [duplicate]

If I have to code a Package and these package use a lot of functions and variables. In spite of, using in every call of function or variable with namePackage ...
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### DE: Plotting a functional

I have a function c given below: c = (2 C0)/(2 + Sum[(Δ - 2 Λ[k - 1]) (Q[k, t]/q[t]), {k, 1, n}]); Here the function ...