0
votes
1answer
17 views

Diagonal minors of matrix

I need to calculate the minor of a matrix. I am going to use Mathematica example here, In[1]:= (mat = Table[i^2 + i j + j^3, {i, 4}, {j, 4}]) // MatrixForm; Minors[mat, 3, Identity] // MatrixForm; ...
-1
votes
0answers
14 views

How use part on a simple matrix to extract individual elements, not rows or columns [duplicate]

I am mystified by how the function Part works given that I have tried many times to extract simple elements of a matrix. My matrix is ...
0
votes
0answers
5 views

module function giving Null values for the following code(Stiffness Matrix Problem): [on hold]

The module function giving Null values for the following code(Stiffness Matrix Problem): ...
0
votes
0answers
19 views

Deleting rows and columns to get submatrices? [duplicate]

I did not think that this would be difficult to find but how do I drop rows and columns from a full matrix? For example, I would like to delete the last row and first column but have trouble making ...
2
votes
2answers
67 views

How to change the form $A\cos \omega t + B\sin \omega t$ into the form $\sqrt{A^2+B^2}\cos(\omega t-\phi)$

I'm preparing notes for teaching next week's class in differential equations. My hand calculation solution of $$y''+192y=0, y(0)=1/6, y'(0)=-1$$ is $$y=\frac16\cos 8\sqrt3 t-\frac{\sqrt3}{24}\sin ...
2
votes
3answers
49 views

Iterating over a list, in a functional way

I have learned a lot about functional programming just from messing around in Mathematica, but I've come across a problem that I don't know how to solve in a "functional" way. Any help would be ...
0
votes
0answers
10 views

Use ParametricNDSolve with Plotting

I am attempting to solve a differential equation of the form $$ \frac{dx}{dt}=ax+by \\ \frac{dy}{dt}=cx $$ with parameters $0<a<1$ and $a,b,c \in \mathbb{R}$. I am able to use NDParametric ...
0
votes
0answers
8 views

Factorial Formula 1∗1!+2∗2!+…+x∗x! = (x+1)!−1 [migrated]

The following relation can be easily proved with the help of Mathematical Induction 1∗1! + 2∗2! + ... + x∗x! = (x+1)!−1 However, for large value of x the result may escalate really quickly. ...
0
votes
0answers
17 views

NDSOlve - 1D wave equation with boundary

I am currently trying to solve the 1D wave equation with Mathematica: $$c^2\frac{\partial u}{\partial x^2}=\frac{\partial u}{\partial t^2}$$ I want to do so for a cantilever with a tip mass: One ...
0
votes
0answers
11 views

How to converrt RGB to YCbCr [duplicate]

While converting rgb to Ycbcr, do we get values as floating point numbers? I would like to have Y, Cb, Cr values as integers. Is it possible?
0
votes
1answer
24 views

How to define a function [on hold]

How can I define a function which depends on a function of x? Something like this f[u[x]_,u[x]']= u[x]' + a [x] u[x] +b[x] I think I wasn't enaugh clear. If I define this function: f[x_]=x^2 and I ...
0
votes
1answer
17 views

Elements inside arrays seem to be strings rather than signed numbers, at least Mtmca doesn't treat them as signed

When I have code like b = Array[Subscript[be, #] &, {3, 1}] b = b /. {Subscript[be, k_] :> Subscript[-be, k] /; k>1} I am noticing that Mathematica ...
3
votes
3answers
73 views

Replace elements in matrix to make it symmetric using automated procedure

I am generating a matrix using (mat2 = Array[Subscript[a, ##] &, {4, 4}]) // MatrixForm but would like to force Mathematica to make it symmetric. Thereby I ...
6
votes
1answer
68 views

Strange behavior when setting NumericQ of a symbol

It happens both in v9&v10. If you try this a^0 a^0 (1/a)^(3/2) a^0 (1/a)^(5/2) Mathematica returns 1 (1/a)^(3/2) (1/a)^(5/2) It's trivial. ...
1
vote
1answer
57 views

Issues with Arrow and Graphics3D [on hold]

I'm trying to plot a simple picture: a plane with a circle in it, and three vectors in the curve. Mathematica keeps saying that the array "has the wrong dimensions for a graphics coordinate list" and ...
0
votes
0answers
43 views

Nothing showing up on complex contour plot [on hold]

I am trying to graph the following function, where z:=x+y*I z(Conjugate[z]+2)=3. But with my code nothing is showing up. I've tried many different scales so something must be wrong with the actual ...
6
votes
0answers
51 views

Bug with password locked: Encode -> Import -> StringToStream -> Get

Let's save a definition. Encode it with password/key and Get it again. We will not use Get ...
11
votes
1answer
70 views

Adding Trace produces error messages

This is very strange. As I was trying to debug this problem, I noticed when I add Trace then I get lots of internal errors generated. This also happens the first ...
0
votes
1answer
40 views

How can I round a number up with two decimals? [on hold]

My problem is, that I have to round a number with many decimals to a number with two decimals. For example: The number is 3.467. Now I want to get 3.46. I tried it with Round[3.4647,0.01], but I only ...
4
votes
1answer
49 views

Problem with Simplify, Sqrt, and Set: What's going on?

I am having some trouble getting Mathematica to simplify an expression of the form Sqrt[x]*Sqrt[1/x], where x>0. The problem is that x is assigned to some complicated form by the time Mathematica ...
0
votes
1answer
65 views

Plotting Complex Numbers - Functions of Complex Numbers [duplicate]

So I have to generate a few different plots with z, where z is a complete number... z[x_, y_] := x + y*I F[z_] := (25*Pi*z*I)/(1 + 10*Pi*z*I) First, I need to ...
1
vote
1answer
67 views

How to find and verify relationships between functions?

MMa gave me a complicated result involving Hypergeometric0F1's. It was much less complicated after I discovered this identity: ...
0
votes
1answer
19 views

Size of the box using Manipulate function

I am using the following command: Manipulate[Graphics[Arrow[{{0, 0}, {a Cos[ω t], a Sin[ω t]}}]], {t, 0, 10, 0.1}] In order to display a vector in circular ...
1
vote
1answer
37 views

Problem with converting \frac into mathematica output [duplicate]

Please help me with the following problem: TeXForm[2/3] The Answer is correct: "\frac{2}{3}" I don't understand why ...
1
vote
0answers
85 views

How to find soccer balls in an image?

I have 10k images and I need automatically remove only soccer balls, excluding other types (volleyballs, baseballs, etc...). I'd like to use computer vision methods of V10 to find their masks and ...
1
vote
1answer
64 views

Notebook downloaded from web giving error message

Just bought a copy of E. J. Mcinnerney's textbook Computational Explorations in Magnetron Sputtering. However, when I download and try Chap2.nb from: ...
-1
votes
1answer
39 views

Graphing a vector [duplicate]

I have a vector (in physic) designated asF1=250cos(60)i+250cos(60)j+250cos(45)k, and i would like to see it in a 3D graphic with the axis centered at the origin, after what i would include other ...
0
votes
0answers
40 views

Increasing CPU usage on Mathematica on a Product [on hold]

I hope someone can help me: I tried Parallelize, ParallelTry and others with AbsoluteTiming, and in every case the time was the same: what I have to do to calculate a Product in mathematica using all ...
0
votes
0answers
35 views

combining separate data into pairs after reading from excel so I can run regression

I have the following code that reads data from an excel spreadsheet: ...
2
votes
1answer
56 views

Combining MapAt and MapIndexed

The very last example in the documentation for MapAt is: MapAt applies f repeatedly if a part is mentioned repeatedly: ...
0
votes
1answer
51 views

How to plot and visualize a single linear vector in 3D? [on hold]

I have a vector (in physic) designated as F1=250cos(60)i+250cos(60)j+250cos(45)k, and i would like to see it in a 3D graphic with the axis centered at the origin, after what i would include other ...
1
vote
1answer
61 views

Function equal to Ctrl+Shift+I

No, it's not InputForm. Consider this example: ...
0
votes
1answer
39 views

Usb-harddisk and raspberry

Mathematica on raspberry. External media access. I have a usb harddisk, which is recognized by the system, but apparently not known to Mathematica. The disk is not seen when I try to open files from ...
1
vote
0answers
43 views

Mysterious message posted when I move the cursor in a custom function

I wrote a function called CPlot for complex plotting which is supposed to act a lot like Plot in its input format, but ever ...
2
votes
3answers
161 views

Function to calculate average of multiple lists

I have several lists of experimental data f[x] with different intervals Δx including some noise. ...
0
votes
1answer
57 views

Apply function on 2d array [on hold]

I have a function taking three variables as arguments. I would like to apply it to several random values. So I first created a table of 3 by 10 random values using: ...
6
votes
0answers
50 views

Why can't I abort main evaluation from ScheduledTasks (Service Link)?

FrontEndExecute[FrontEndToken["EvaluatorAbort"]] is equivalent of the menu item: Evaluation >> Abort. It works with ...
0
votes
0answers
39 views

How to properly pass function as argument here? --> NMinimize & NIntegrate involved

I had a problem of a similar kind here which was solved. Now after changing a few things in my problem setting I am suffering from the following problem. Let me first introduce methods/functions that ...
2
votes
2answers
51 views

Dynamic visualization of two histograms

I have two histograms histo1 and histo2: ...
1
vote
1answer
82 views

Force Mathematica to return numerical answer to (relatively) complicated differential function

I am trying to take the Laplacian of the LogDet of a 2x2 matrix that I call V\[ConjugateTranspose].V, and actually get a number out at the end. Why does Mathematica ...
0
votes
0answers
55 views

Low CPU usage. How to increase it? Should I?

I'm running a programme, and below are some graphics from the resources monitor from windows 8, while running my programme in version 9 of mathematica. Sorry for the foreign writings in the pics, but ...
0
votes
0answers
32 views

Find minimum summation and constraint values [on hold]

how can I get mi value to minimize this equation..?
0
votes
1answer
53 views

Equivalent parametric plots don't look the same

ParametricPlot[ {1, Tan[t]}, {t, -Pi/3, Pi/3}] ParametricPlot[ Sec[t] {Cos[t], Sin[t]}, {t, -Pi/3, Pi/3}] The second parametrization does not plot like the first, ...
0
votes
0answers
49 views

How to extract data points from an image of a log log plot? [duplicate]

I have a picture of a log-log plot, taken from a paper and I want to extract the data points so I will be able to plot them again along with results of my own solution. I would appreciate your help. ...
1
vote
1answer
35 views

What is wrong with my following vector plot

I am trying to plot the following: ...
0
votes
1answer
27 views

Force ReplaceAll to output vector of same length

I would like to do a replace in an expression... a = t; b = 1; a/.t->Range[1,5] (*returns: {1,2,3,4,5} *) b/.t->Range[1,5] (*returns: 1 *) but I ...
4
votes
1answer
393 views

Something interesting about Pi, but something seems amiss

I saw something interesting about text-analysis - bigrams - in Basic Text Analysis in Mathematica I wondered how the bigrams of Pi's digits might appear. As expected, take enough terms and every ...
0
votes
0answers
36 views

Parametric Plot and Dynamic [on hold]

I have: ...
1
vote
2answers
53 views

How change style of InputField in a Manipulate?

Is it possible to specify a style, e.g., font size, for InputField type controls inside a Manipulate and if so, how? For ...

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