# All Questions

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38 views

### What does tag plus protected mean in this case? [closed]

I am trying to define a function for future NDSolve use oweqn = (1/(c)^2) D[y[t, x], {t, 2}] - D[y[t, x], {x, 2}] + k1 y[t, x] = 0 Where I predefined $c$ to be a ...
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### Export is not clearing memory

Version: all 12.x OS: Windows 10 and MacOS I am having an issue with Export not clearing memory after it is done with exporting to an .mx file. I have reviewed other posts concering memory issues with ...
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### NMaximize - global maximum fail - How to?

Problem : Let x,y,z be non-negative real number whose sum is 1. Find maximum of 0.2x + 0.2y + x^2*z + y*z^2 What I did first was reducing variable. ...
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### how to efficiently use a time series database to plot Barcharts or LinePlots

I have the following input: ...
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### How to add weights in fitting?

I have a set of data as: data = {{0, 0.046}, {40, 0.111}, {80, 0.291}, {120, 0.808}, {160, 1.742}, {200, 3.319}, {240, 5.017}, {280, 5.503}, {320, 5.897}} With ...
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### NetNestOperator with custom input / output ports

I'd like to use NetNestOperator on a NetGraph that has custom input / output port names, such as ...
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### How to get the contents of clipboard in a variable?

If I copy something into the clipboard then use var=Paste[]; I get Null in the var and the ...
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### What is the best way to flatten a nested list?

I have a list called matcoeffE which has dimensions {10, 9, 7, 2}. However, I want to build a matrix with dimensions ...
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### Define the heat capacity Cp as constant values in the current version of Mathematica (Coupled PDEs)

I am trying to model a 2d heat transfer in fluid flow with nonlinear heat capacity Cp (e.g. Cp=1 + T[t,x,y]). This benchmark problem is described as: the left side of the plate is heated, and the ...
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### how to compute fractional function in mathematica? [closed]

I am trying to compute fractional function in mathematica using: https://resources.wolframcloud.com/FunctionRepository/resources/FractionalD for example: ...
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### Most efficient way to find instance of inequality being true (of polynomials with square roots)

I am trying to show that a given inequality is true for some triple but I am having trouble finding anything. Here is a tiny version of what I am working with: We define the following polynomials <...
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### Improving plot execution time

Let me first show what I'm trying to do, and then I will ask the question. I defined three function ...
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### Loops for every time step on a time-dependent function coming from NDSolve

I have a time-dependent function a[t], which comes from solving various differential equations. Therefore, to obtain the different values of ...
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### velocity four-vector definition by xAct

I want to define the velocity vector by the following relation and evaluate the norm of the vector by using the Minkowski metric. I have defined the tensor x (position tensor) in xAct, but I don't ...
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### Plot a sum of vectors using inline free format or wolframalpha. What is the hidden code?

Using Wolframalpha or inline free format you can obtain a nice representation of a sum of vectors. An example is shown below. Whish is the hidden code? (or a code that make the same representation). ...
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### Regression of a set of (2-element) vectors on another set of (2-element) vectors

As a trivial example, here are two vectors: f = {{1, 1}, {2, 2}, {3, 3}, {4, 4}} s = {{-1, 2}, {-2, 4}, {-3, 6}, {-4, 8}} It is instantly clear (apart from my ...
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### Behaviour of Coefficient[] for negative exponents in rational expressions

I've observed a puzzling behaviour of Coefficient[] for negative exponents and I'm wondering if I was always just relying on undefined behaviour or if there is a ...
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### Currency Interpretation for VND

As I was helping an OP with a question involving Vietnamese currency, I didn't realize at the time that the currency amount was not being interpreted accurately (or so I think now). Apparently, the ...
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### VectorScaling on VectorPlot produces vectors of wrong length

I'm trying to plot the following VectorField: VectorPlot[{x/Sqrt[x^2 + y^2], y/Sqrt[x^2 + y^2]}, {x, -5, 5}, {y, -5, 5}] I want to use a VectorScaling-option such ...
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### plotting simple harmonic oscillator problem [closed]

1.3 A simple harmonic oscillator consists of a mass m and a spring with stiffness constant k. It moves in one dimension x(t) with velocity v(t) where x(t) = A cos(wt + φ) and v(t) = -x(t) = −wA sin(wt ...