# All Questions

270 views

### How to draw a tropical surface?

By definition, a tropical surface in $\mathbb R^3$ is the set of points $(x,y,z)$ where the maximum $f=\max(f_1,f_2,\dots,f_n)$ is attained at least twice, here $f_i$ stand for some linear functions ...
86 views

### Calculating a function repetitively without using a For loop

In my programme I have defined all these functions: ...
51 views

### How to preserve “itemize” format when converting mathematica notebook to a latex file?

When I convert a Mathematica notebook containing following cells with "itemize" format to a latex file these cells become raw text format like this: ...
118 views

### Is there the possibility to write many times a value in definite list of file1.nb?

The commands testData = RandomReal[{0, 1}, {1, 1}]; Export["C:\\Users\\Alex\\Desktop\\1\\file1.nb", testData]; write the “testData” (value generated by ...
173 views

### Complex numbers from two arrays with Real and Imaginary parts

I have two arrays, containing the real and imaginary parts of a list of complex numbers. Re = {{Re_number1},{Re_number2},...} Im = {Im_number1},{Im_number2},...} ...
83 views

### Fill an array, symmetric with respect to its centre

I want to create an array that must be symmetric with respect to the centre of it, as in the following example: 0 1 2 3 4 3 2 1 but, instead of having such ...
154 views

### Problem with using GraphicsColumn

I have three plots defined as: ...
171 views

### Drawing nodal lines of wave equation

I am new to Mathematica and I want to produce the following figure wich represents the nodal lines of wave equation. Can anyone help?
92 views

### How to draw phase portrait graph for nine system of differential equations in mathematica? Can have a code for darwing this? [closed]

The differential equations for the transmission dynamics of HIV/AIDS are given as follows: ...
215 views

### Assumptions with patterns

I want that Mathematica assumes every symbol like Subscript[s,i] to be evaluate as a real and positive number. I have tried ...
75 views

### Integrating ODE's

I have: $$m\frac{dV_y}{dt}=-k\cdot V_y-mg$$ where, $V_y$ is velocity in the $y$-direction. I have the initial condition Vy[0]=40 Sin[40 Degrees] and ...
26 views

### How do I get Mathematica to evaluate symbolic linear algebra [duplicate]

First of all, I am VERY new to Mathematica. That said...I have defined vectors as: e1=2x-y and e2=x+y (x and y are orthonormal). I also defined the dot products of x and y in Mathematica. I want to ...
165 views

### Finding gradient of equiangular (logarithmic) spiral

I encountered a problem in determining the gradient in cartesian coordinates (x,y) of a logarithmic spiral (or equi-angular spiral) profile. The log-spiral definintion is as shown below (similar to a ...
54 views

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93 views

### Complicated equation solving

I want to find the maximum point or optimal value $y$ of Rx1[y_, a_, b_]. ...
93 views

### Time series package in mathematica 9

Is the time series package already installed in Mathematica 9? I have already installed Mathematica. Do I need to install the time series package? If so, from where? or should i go for mathematica ...
66 views

### How can I perform this integration in Mathematica? [closed]

I am new to Mathematica. I want to find the integration of the following expression: $H(f)=T\left(\frac{sin(\pi f T)}{\pi f T}\right)^2$ Here, $T=1.127e-7$ I want to integrate this function for a ...
1k views

### How to Fold over lazy lists and over tasks, just as with Lists?

Many modern languages, such as Haskell, feature lazy lists, which can model infinite sequences of values, albeit synchronously. Lately, the reactive programming movement has shown that asynchronous ...
28 views

### ContourPlot looking choppy [duplicate]

I want to plot a simple curve, the bifolium (x^2+y^2)^2-yx^2=0. I entered n=1/2; ContourPlot[(x^2 + y^2)^2 - y x^2 == 0, {x, -n, n}, {y, -n, n}] into mathematica and got the plot which looks very ...
58 views

### listcontourplot on a sector of a circle [duplicate]

s = Import["Desktop/tension.xlsx"]; ListContourPlot[s, Contours -> 10, PlotLegends -> Automatic] In fact, it is a contour of a circular part from (2,0) ...
152 views

### Filling Piecewise Function leaves gaps [duplicate]

When I use the fill feature to shade the area between the curve and the x-axis, there is no fill when x=2. I don't understand how this is possible since the function is defined there. Any help to fill ...
99 views

### Problems solving/plotting a differential equation

I am trying the following: Plot[DSolve[{1220*x''[t] + 1000*x'[t] + 35600 x[t] + 4500*x[t]^3 + 2135 == 0, x[0] == 0, x'[0] == -5}, x, t], {t, 0, 10}] Could ...
109 views

### Filing matrix by bands [closed]

I need to fill a matrix, CSI, by taking elements from an array, inverse, which is the Inverse Fast Fourier Transform of an array ...
94 views

### How to Reap data from a ScheduledTask?

Here is an amusing little function mapped over a range just to iterate it. It ignores its argument and works entirely by side-effecting a global variable: ...
187 views

### Detecting nearly simultaneous WhenEvents in NDSolve

I am trying to solve a system of (many) coupled nonlinear ODEs. I need to decouple some of the equations (i.e. set the time derivatives of some of the dependent variables to zero) at various points in ...
57 views

### Update NumericalFunction in NDSolve

I have NDSolve StateData from an NDSolve ...
216 views

### Evaluating a numerical integration with infinity as limit

I am trying to evaluate a numerical integration (to get an expression of the constant Ω) Suppose that h[x_] := 1/(1 + a x^2) ...
187 views

### Make continuous 3D tube out of 2D image (Mathematica 8) [duplicate]

I have the following image with transparency: which I want to paste repeatedly into a 3D space to make it like a tube, something like this (but denser): I tried using the code from here but it ...
134 views

### How to adjust excel data for NonlinearModelFit?

I'm really new to Mathematica and I'm facing a problem and would really appreciate some help! Maybe my question is similar to one described in How to fit 3 data sets to a model of 4 differential ...
99 views

### Trouble with ToString and StringForm

The command ToString[StringForm["SomeText= as well as OtherText=.", "textA", "textB"], FormatType -> InputForm] produces the output ...
215 views

### Vector Plot of a linearly varying cantilever

I want to drawing with Vector Plot a deflection and slope of a linearly varying cantilever. And with Contour Plot it works but with Vector Plot it didn't. Here is the code: ...
72 views

### Setting Fixed Axis

Is it possible to prevent the values of axis of a 3D plot from moving? If I run this code: ...
218 views

### Customizing X-axis label for groups of 7 (weeks)

I have a set of data organized as a list where each list entry represents a day of the week. The data starts on a Sunday. It represents about 5 months of data. Each element of the list is ...
88 views

### sparse array with list [closed]

i'm trying to populate a sparse array with lists in certain positions, i tried the following code, ...
84 views

### 3D box dimensions

How can I set the dimensions of the box of a 3D function, without influencing the function? For example I want to see this function ...
214 views

### How to map over inner keys of nested Associations?

Considering an association: <|"a" -> <|aa-> "asc", bb-> "asd", cc-> 0, ImageType -> "asd", dd-> "asd"|>|> How can I make the inner ...
118 views

### Problem with AxesOrigin option in ListPlot

Please compare the output of these two similar codes: ...
778 views

### Writing a circular matrix

I have two square matrices, $A$ and $B$, of the same size, say, of $m \times m$. What I want is to write a programme/function of three variables, $A$, $B$ and $n$, that outputs the $mn \times mn$ ...
112 views

### ParametricPlot3D won't show [closed]

I want to see the image of a tube made from a space curve. I define the surface using Frenet-Serret frame but the software does not show me the plot. What might be wrong with my code? Thank you.
103 views

### How can I generalize this interpolation function? [closed]

I have a data set where I want to evaluate a manual interpolation function. The part shown below expands up to the 7th power currently. I was wondering if it was possible to generalize this part of ...
65 views

### How can I manipulate this list?

I performed a loop with Table where I solve a system of 4 equations that depends on two parameters: eta and p. I create two lists for each parameter as follows: ...
96 views

### How can I use L.Shifrin s code formatter package better [closed]

in the document of HoldAllComplete, it says: Evaluate cannot be used to override HoldAllComplete.. for example, when I'm ...
104 views

### Problem with MeshOrderAlteration to create a 2nd order ElementMesh

After working on this 2D domain, I'm trying to reproduce the same ideas to create a mesh of a sphere composed of QuadElement, instead of more simple and common ...
231 views

### Changing the ExtrapolationHandler Function in Any Interpolation

This is a related question to What's inside InterpolatingFunction[{{1., 4.}}, <>]? and Suppress extrapolation of interpolating function in a ContourPlot. When interpolating a set of ...
274 views

### How to switch from array to string?

Considering we have an array: a = {2/3, 4/5, 9/7, 3/7, 1/7, 1/9}; How can I get this to be: "2/3 4/5 9/7 3/7 1/7 1/9" ...
158 views

### Function in Mathematica 10.1, but not in CDF Player 10.0.2

Mathematica 10.1 has a new function MinMax. It is absent in the current CDF Player 10.0.2. CDF files that use MinMax leave the function unevaluated, and thereby produce errors. One approach would be ...
91 views

### Create an array with certain conditions and use it to fill a matrix [closed]

I am translating my code from Python to Mathematica. Here is a piece of my Python code: ...
133 views

### Show Full Output button broken for all large outputs

I use Mathematica 9.0.1.0 on Mac OS X 10.10.3. As an example of my issue, we can follow along with the example from the documentation page for \$OutputSizeLimit. ...
50 views

### Alter evaluation order when applying scalar multiplication to function

Consider the following program: g = 2f; g[x] (* (2f)[x] *) Is there any way I can change the above expression to have it return ...
80 views

### Why won't equal trig expressions simplify to the same form? [closed]

Trying to get Mathematica to do trig always stresses the hell out of me ... Why. won't. it. do. things?!? Why does ...

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