# All Questions

46 views

### PDE solved with NDSolve. How can I plot the partial derivatives of the solution? [on hold]

I solved this PDE pde = D[B[t, T, r], t] + a*(b - r)*D[B[t, T, r], r] + 1/2*sigma^2*r*D[B[t, T, r], {r, 2}] - r*B[t, T, r] == 0 with this parameters and ...
117 views

### Use of Ito's lemma in ItoProcess

In the documentation for the ItoProcess it says: Converting an ItoProcess to standard form automatically makes use of ...
45 views

### Are there examples that arrange graphs or plots with Mathematica?

If we have 4 graphs or output plots, could we arrange them and merge in one graph elegently?
26 views

### WeatherData: Time zone conversion [on hold]

Using the WeatherData we can change the time zone. Like so. ...
47 views

### Evaluate recursive funtion as a whole before computing a recursive step

I'll try to make a basic example of my problem with $n$ being an array of elements, ex. $\{1,2,2,3,3,3\}$: If i have a sum which needs a computed value i would like to compute it beforehand and store ...
130 views

### How can I obtain more significant digits? [duplicate]

I type f1[x_] := 12 x^5 - 975 x^4 + 28000 x^3 - 345000 x^2 + 1800000 x N[f1[15.5], 15] and obtain 3.74112*10^6 BUT It´s not true!!! the result is larger than ...
39 views

### QuantityVariable usage

When I try to run the following code, Mathematica gives me an error message: "Solve was unable to determine the units of quantities that appear in the input." ...
34 views

### in the part assignment is not a symbol, create different matrices with a loop

Im trying to assemble new matrices from some previous matrices I have created, but I can´t. What Im trying to do is the following: 1) I have different matrices: ...
71 views

### Sorting non-numerical lists [duplicate]

The Sort function will by default sort from lowest to highest. In[1]:= Sort[{3, 1, 4}] Out[1]= {1, 3, 4} However, if the list ...
33 views

### Writing a text to a file including af mixture of signs

I'm trying to write this to a file: j/?xml version="1.0" encoding="UTF-8"?> However, when using WriteString, the "-marks are not accepted. If I use Write, however, the "-marks are accepted, but ...
37 views

### Applying functions repeatedly on parts of complicated expressions

I am dealing with expressions like  \textrm{expr}=5D_{4,1}\langle12\rangle\langle23\rangle\big(-\langle15\rangle^2\langle24\rangle\langle34\rangle + ...
306 views

I have a ragged list ragged = {{a,b,c,d,e},{x,y,z}} that I would like to trim (on the right) to be rectangular. The desired result is ...
40 views

### How should I define functions that distribute over Plus?

I have a linear function which also follows the chain rule (it is a derivation), so I defined it recursively, following a Wolfram tutorial (which I've misplaced) and other related answers: ...
517 views

### Can Mathematica delete some of the 0's from a list?

I have a list: {1,2,3,0,0,4,5,0,0,0}. I want to delete the 0's occurring after the last positive integer. In other words, I ...
50 views

### Relaxation of Mass-Spring System with Pinned Masses

Problem Assume that four masses are connected to each other by springs while two of them are pinned down at their initial positions. Find the position of masses when system is at its minimum ...
98 views

### How to get output in a specified format

In Fortran, we can easily get the stardard and easy output format. Now, we only focus on the Integer output. See here How to realize this kind of output as formatted text file using Mathematica ? ...
16 views

### The index number of an isolated critical point = 1+(e-h)/2 [migrated]

I know that the number of elliptic (e) and the number of hyperbolic should be even. But i find a difficulty in coming up with a proof for this
57 views

### Delete data were y = “NS” in a list with elements {x, y} [duplicate]

I have a list of data {x, y}and not all of them have actual values. They show as {x, "NS"} or ...
133 views

### Converting strings of the form “1.34e5” to real numbers? [duplicate]

ToExpresssion doesn't understand real numbers of the form "1.34e5". How do I convert the string ...
33 views

### operating lists [on hold]

I have 2 lists 25 items, as I do so that data entering this formula ...
24 views

### question of nested for loops with 3 variables [on hold]

hi I got a simple trouble here. this is the question and my solution. does for work with a variable start with other variables? I have no idea why it got a {}. Some one help me out?
18 views

### translation and transformation [on hold]

Triangle PQR has vertices P(O, 0), Q(5, -2), and R( -3,6). Find the 'vertices of P'Q'R' after each translation. (Example 2) 6 units right and 5 units up _ 8 units left and 1 unit down Persevere ...
6k views

### Recovering data points from an image

Unfortunately, some data can only be obtained in picture form (Japanese publications anyone?). Since this cannot be worked with, it has to be converted to a dataset that can; I was wondering whether ...
42 views

### Entering an differential equation in a Manipulate box

Does anyone have an example of a Manipulate demonstration where the user can type into a box the differential equation, time interval, initial condition, and the result is plotted? This possible in ...
21 views

### How to apply substitution when expression contains powers of the quanity

An expression like: a = TrigToExp[ 3 + 4 Cos[u] + Cos[ 2 u]] produces a list of exponential factors: 3 + 2 E^(-I u) + 2 E^(I u) + 1/2 E^(-2 I u) + 1/2 E^(2 ...
619 views

### Built-ins for discrete ArgMax or ArgMin?

Wondering whether there are discrete versions of ArgMax / ArgMin, that is, something that will find the part of an expression at ...
30 views

### Is there a way to define primary keys using SQLCreateTable?

I would like to create a db table and specify the primary key columns using the command SQLCreateTable. I know I could use SQLExecute but in this case I'm only interested in the right parameters for ...
98 views

### Catch and Throw command [duplicate]

I am trying to find the time and maximum height of a projectile motion with air friction however Mathematica is "running" for a really long time and not giving an answer. Is there something wrong with ...
42 views

### How do I simplify Interval[{x,x}] to x?

How do I simplify Interval[{x,x}] to x ? Simplify and FullSimplify do not seem to do it.
212 views

### Why can I not replace a Dataset using a rule?

Simple replacement of a Dataset object does not seem to follow the expected behavior... Dataset[{}] /. _Dataset->1 Returns the empty Dataset not 1 as I would ...
29 views

### How to input an adjacency list?

I am a beginner user of Mathematica, and I have an assignment to construct a graph given n (number of vertices) and an adjacency list. My idea was to make a For cycle that repeats n times, and for ...
500 views

### Flatten nested lists

I have a list as follows lis= {a, {{{b}, {c,d,e}}, {{f}, {g,h,i}}}} which I would like to flatten to ...
57 views

### Solving a single-variable equation mixed with exponential and algebraic

Trying to solve for x Solve[((a - 1) (1 + d x^2))/(a (Exp[b x + c] - 1)) - e == 0, x] in terms of the constants a,b,c,d, and e. Mathematica says "This ...
55 views

### selection based on values of other list

I want to make a selection of a list based on the values of a other list list1 = { {1, 2, 3, 4}, {1, 2, 5, 6}, {2, 3, 4, 5}, {5, 6, 7, 8}} list2 = {1, 2, 3, 4} ...
25 views

### How to set options in Option Inspector in notebooks by running commands?

It involves an order of magnitude more mouse clicks and visually searching text to set some option in the Option Inspector (which is a UX nightmare) than doing that in a notebook by running some ...
79 views

### AutoGeneratedPackage Formatting

If you do Ctrl+Shift+o you open an option inspector. And then you can enable ...
607 views

### Join lists with nested list

Is there a way of smarter way of joining list of the form l1 = {a,{b,c}}; l2 = {d,{e,f}}; l3 = {g,{h,i}}; To obtain ...
135 views

### Clicking phase plane with mouse

Here is what I have thus far: ...
2k views

### How can I implement the method of Lagrange multipliers to find constrained extrema?

I want to form the function $h=f-\lambda_{1}g_{1}-\lambda_{2}g_{2}$ where $f$ is the function to optimize subject to the constraints $g_{1}=0$ and $g_{2}=0$ so that I can solve the first partial ...
28 views

### Setting Marker Line widths in Legend

I have read all these posts and can not get this to work. I am trying to increase the width of the line in the legend. I have tried SwatchLegend, ...
102 views

### Using Throw within ParallelDo

I've noticed that I can't Throw from within a ParallelDo in the same way that I can from inside Do. For instance, the following will work as anticipated with Do but not with ParallelDo: ...
27 views

### Exploration of the region satisfying the follow conditions

I posting my code which I am using to find data points satisfying the following condition, but from this I can only able find data points of the certain curve. But I want to find the whole region ...
108 views

### Image3D with values outside of the range [0,1]

I am writing some functions in Mathematica for representing MRI anatomical image volumes. The natural way to represent such a volume seems to be as an Image3D form. However, I've noticed an ...
43 views

Here is the question. Consider the function f(x) = (2-x)/(x+1). -Find all points on the graph of f where the tangent line is perpendicular to the line y=4x. -For each point, report the equation of ...
11 views

### to solve this combinatorial optimization problem [migrated]

\begin{align} &\max_{C,E,S} \begin{aligned}[t] &\sum_{t=1}^{T}\sum_{k=1}^{K}min\left\{{\mu(\alpha_{k},e_{k}(t)),\gamma s_{k}(t)}\right\} \end{aligned} \notag \\ &\text{s.t} \notag \\ ...
41 views

### Reading Barcode/QR Code from webcam

I need to make a Barcode/QR code reader from video. It could be captured from an image with a built in code, but I could not figure it out how it could be done by video. Let me tell the big picture. ...
29 views

### Reading a .txt file with numbers

The .txt file is: tb_FeSe_22_12_2014.csv 0.00102786 (-0.000421863,1.58589e-09)(-4.04766e-05,2.67116e-07)(-8.4396e-06,-1.54976e-07) I would like to Import it to Mathematica such that I have: ...
125 views

### Deleting one of each chosen elements in a list containing duplicates [duplicate]

I want to delete one of each (and not all) selected element in a list containing duplicates. For example i have the list: $\{1,1,1,2,2,3\}$ and i want to delete $\{1,3\}$ so the leftover should be ...