# All Questions

122 views

### Numerical solution to two non-linear coupled differential equations [closed]

I am trying to solve two differential equations representing the position of an object in space. I have specified arbitrary initial conditions. ...
289 views

### Integrate wrong for absolute value of trig function

I was trying to get $\int_0^1 \lvert \cos(2 \pi k x) \rvert \,\mathrm{d}x$ for $k \in \mathbb{Z}$, and was surprised by the result (using Mathematica 10.0.1.0): ...
200 views

### Simplify a series expansion including product and multiplication

I have a following expression $$f=\Pi_{i=1}^n \left[ 1 + \frac{1}{t} +\frac{ (m+i)}{t^2} +\frac{ (m+i)^2}{t^3} + \cdots \right]$$ here $m,n,t$ are positive integers. I want to obtain a series ...
171 views

### Getting errors when I try to evaluate code taken from Trott's Mathematica Guidebook for Graphics

I would like to learn how to make high quality images in Mathematica. In my pursuit, I have come across Michael Trott's Mathematica Guidebook for Graphics. I have been trying some of the examples, ...
60 views

### How do I generate a list of delayed rules? [duplicate]

I want a list like this: {x :> Print[1], x :> Print[2], x :> Print[3], x :> Print[4], x :> Print[5]} I tried: ...
104 views

### Providing wrong answer on integral $\int_{-\frac{2}{3}}^{\frac{2}{3}} \left(\text{Ln}\left(\cos ^4(x)\right)+1\right) \, dx$ [closed]

I tried to evaluate the following in mathematica $\int_{-\frac{2}{3}}^{\frac{2}{3}}{1+\ln \left( \cos ^{4}\left( x \right) \right)}dx$ and got the answer as $0.91905 - 3.94746*10^{-16} I$. However, ...
179 views

### How to align rotated BarChart labels? [duplicate]

I'd like to use long text labels for a simple BarChart, but when I apply a rotation to label strings with different lengths the end of the text is no longer aligned ...
357 views

### Compose many Geometric Transformations for 3D Graphics

I'm struggling to understand what would be a good way to compose several geometrical transformations to create a single TransformationFunction to be applied to a ...
252 views

### Can you Plot over some range but apply the “Filling” option over a smaller range? [duplicate]

I would like to shade the area between a function, and a line, but only over a specific range. This range is smaller than the range of the entire plot. The example code and plot below make my goal ...
752 views

### How can I evaluate only a single step of a recursive function?

Let's say have a simple recursive function for the Fibonacci sequence f[0] := 1 f[1] := 1 f[n_] := f[n - 1] + f[n - 2] but I want to see how it will expand in a ...
342 views

### Using NDSolve to solve a system of coupled PDEs

I am trying to solve the Gross-Neveu model in one dimension for a specific soliton initial condition. I am trying ...
157 views

### Display full path of current notebook on title bar?

Is there a setting in Mathematica notebook interface to get the title bar to display the full path to the current notebook?
267 views

### How to combine ListPlot and ListPlot3D

Suppose I have a plane drawn by ListPlot3D and I have one intersection of that 3D image drawn by ListPlot. How can I combine ...
194 views

### Connecting to Microsoft SQL with version 10

After upgrading to version 10, functions relying on a connection to a Microsoft SQL database no longer work. When I attempt to open a connection with something like: ...
494 views

### Upload a file using a WolframCloud WebForm

I tried to create a Webform in WolframCloud that asks/browses for a file and then uploads it to a specific folder. The following are the directions I investigated but it does not work: ...
128 views

### Equivalent command to the Maple indets command

This carries on the discussion here and here. I had mistaken Variable[] to give you ALL variables in an expression, but apparently, it is not meant for that. ...
72 views

### Creating a matrix from a list of simultaneous equations

I have a list of n simultaneous equations of the form, w A[n] = (K[n,n+1]+K[n-1,n])A[n] - K[n,n+1]A[n+1] - K[n-1,n]A[n-1] ...
99 views

### Pattern for finding matches that are different [duplicate]

I am trying to solve the following problem. I have tuples of size 3 {{a, b, c}, {a, b, c}, {a, b, c}} I would like to find cases where all the elements in a ...
47 views

### Automating constructor definitions (OptionValue eval time)? [duplicate]

I'm settling in on a programming pattern for "constructors." I can illustrate the pattern with the following example, which defines a constructor newBar for ...
361 views

### 2D smoothing spline interpolation

Does Mathematica have 2D smoothing spline interpolation built in? I requires an interpolation method with smooth first derivatives and cubic bivariate splines fulfill this nicely. In python I would ...
414 views

### Simplifying general solutions of differential equations (driven harmonic oscillator)

Solving general differential equations in Mathematica usually leads to somewhat unsightly results. As an example, consider the solution of the driven, damped harmonic oscillator: ...
135 views

### How can I connect the local minimum-value points between a series of curves by dotted lines?

I have a set of data obtained by NDSolve. After I plot it, I want to indicate some feature of the curves. For example, I want to link the local minimum-value points between these curves by dotted line ...
90 views

### Using expressions in Text

I want to use Text to add some labels to a graph and was wondering if it is possible to use expressions inside Text? Here is a MWE of what I am trying. ...
540 views

### Total much slower in version 10

Issue introduced in version 10, fixed in 10.0.2 Compilation nowadays may give very fast functions. Here is an example for finding the sum of a list of machine numbers, just as the built-in function ...
136 views

### How to remove recursion, and write it functional and efficient way?

I wish to implement the following recursion efficiently. ...
84 views

### Conditional replace of a column

Im trying to replace the value in the Nth column of a list if a condition is true, returning the modified list. I've tried modifying the answer from 61219 and been through most of related questions ...
232 views

### Difference between double quotes

I have a notebook and I enter something like PlotLabel->"my label with dynamic number "<>ToString[strange] and I get errors like However, the double ...
307 views

### Find extreme values in a polynomial expression

I have been hunting down and could not find an answer to my question. As I've now been struggling for quite a while and believe it is a simple trick that's preventing me from getting over this ...
66 views

### What does this Append expression do? [closed]

I have to understand some code. A part of it is written below. Can someone explain to me what it does: ...
295 views

### Help recreating a gif

For my math class I am trying to recreate a mathematical GIF. Here is the GIF I wish to make: At this point I think I have a 3D function that would work to lay the hexagons on to. ...
110 views

### Cluster a time series by labels

I have a time series, tab delimited dataset with the following format ...
682 views

### How to calculate position from 3 dimensional acceleration data?

I discussed this problem yesterday with Pickett here. We concluded that the best solution may be just Interpolate and then ...
218 views

### How to deal with the condition $u_i=u_{i+1}$ in B-Spline basis function?

The defintion of B-Spline basis function as shown below: Let $\vec{U}=\{u_0,u_1,\ldots,u_m\}$ a nondecreasing sequence of real numbers,i.e, $u_i\leq u_{i+1}\quad i=0,1,2\ldots m-1$ N_{i,0}(u)= ...
82 views

### Use conditional expression inside With

I want to assign a number to an internal variable, depending if a specific option has been given, but it seems to fail. Something like: ...
194 views

### How can I get the second derivative and the reciprocal from the result of NDSolve?

I have obtained a result h(x) from NDSolve data. I can plot it data = Import["C:\\Users\\...\\Desktop\\data.dat"]; ListLinePlot@data Now I want to get the 2-nd ...
370 views

### Transform Dataset so it can be used as training set for Classify

Trying to learn the new Dataset features, I am playing with the iris dataset: ...
83 views

### Plotting/Visualization in Workbench?

I would like to ask a question with Mathematica Workbench. The workbench is based on Eclipse. Of course, it would have no problem to add breakpoints and debug, but I wonder if it is possible to ...
564 views

### How to trigger UNIX command-line command from Mathematica notebook?

At UNIX command line, one can run ls -la $HOME. How to trigger this from Mathematica notebooks? Run["!ls -la$HOME"] ...
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### Can I line the mesh lines on a RegionPlot3D up with integer values of the axes?

(Sorry if this is a duplicate, I searched briefly and didn't find anything.) I have region plots in 3D like: ...
60 views

### How to get the subdirectory of a ftp weblink?

For example, I can use FileNames["*",dir] to get all subdirectory under dir if dir is some directory of my local computer. Suppose that I want to get all ...
253 views

### List of tuples without forbidden pair

How do you get a list of tuples in Mathematica that do not include certain pairs of elements? For example, I'm trying to list sequences of matrices of a certain length, and I do not want two adjacent ...
162 views

### Simplification due to recognition of dummy indices in sums?

Today I noticed something weird concerning implicit sums. Apparently, Mathematica cannot recognize dummy indices as such and simplify accordingly. Consider: ...
204 views

### How to re-parse (or re-map) character '.' to user-defined function

The default behavior of the character . between two non-numeric characters is to be interpreted as the infix of the Mathematica function ...
175 views

### Manahalobis distance between two vectors

I want to calculate the Mahalanobis distance between two vectors that represent two points. For example: ...
209 views

### Solve and Reduce with Log finding unexpected root

We give equations like $\ln(1-x)-\ln(x-2)=0$ to our calculus students. This equation clearly has no solution, since $\ln(1-x)$ is only defined if $x<1$ and $\ln(x-2)$ only if $x>2$. Still, the ...
228 views

### Understand MeshFunctions with Intercepts

Bug introduced in 7.0.1 or earlier and persisting through 10.0.2 or later While I've been thinking about this question, I tried to visualize the Intercepts. I use three snippets, actually snippet ...
119 views

I do believe this sort of similar questions had been asked many times, so I have read a LOT. For example this and this as well as many other related posts. But a glance at what my main question is ...