# All Questions

91 views

### Change in direction when a line hits an ellipse? [duplicate]

I'm trying to simulate reflecting light off an elliptical mirror. I currently store the ellipse in the form {center,{radii},rotationAngle} and the ray of light is ...
190 views

### Calculate expected value of piece-wise pdf

I have the following PDF of a random variable: $f(x)=\begin{cases} 1 & \text{if}\ \ \ 0<x<\frac{1}{2} \vee 1 < x < \frac{3}{2}\\ 0 & \text{otherwise}. \end{cases}$ How can i ...
95 views

### Zoom settings other than 50% 75% 100%, [duplicate]

Is it possible to choose a zoom setting other than what's provided at the bottom of each Notebook window (50%, 75%, 100%, 125%, 150%, 200%, 300%)?
202 views

### Ovals of plane curves (and esoteric surfaces in space)

Consider the curve $y^2 - x^3 + x=0$ with $x, y$ real. This curve has two connected components (one bounded, one not), and the question is: how do you get Mathematica to tell you that (if you do: ...
101 views

### Manipulating array

I have got an array like this: A = {{{1, 4, 5}, {3, 7, 15}}, {{5, 6, 9}, {7, 8, 2}}, {{9, 10, 1}, {11, 12, 3}}} I make differences in each sublist a following ...
172 views

### Mathematica multi-dimensional numerical integration default method

I'm performing multidimensional Numerical integrations with mathematica I was wondering what was the default method that mathematica was using. Also i'm changing some parameter inside the integration, ...
201 views

### Simplifying vector expressions

I have some code that calculates Jacobians, but the results contain terms that should simplify or cancel out, but I'm not sure how to achieve this. My code looks like ...
223 views

### Where can I find a good tutorial for stochastic modeling using Mathematica?

I am a newbie in Mathematica and I aim to use Mathematica mostly for stochastic modeling (to develop and analyze models in evolutionary biology). Note that I am not necessarily a great mathematician ...
67 views

Suppose that I have f[a_, b_, x_] := ... I'd like to create a list of n pure functions ...
168 views

### What is the PDF of a variable where a parameter is itself a random variable?

Question How do we analyze in Mathematica cases where a parameter in a Probability Density Function (PDF) varies according to another PDF? Consider the following example... Example The text below ...
194 views

### Solving Differential Algebraic Equations as BVP

I am trying to solve a set of DAEs. -4 \nu (\lambda(s))^{(-1 - 4 \nu)} \theta'(s) \lambda'(s) + (\lambda(s))^{(-4 \nu)} \theta''(s) = -\alpha_y \cos\theta(s) + \alpha_x ...
214 views

### Change the colour scheme in DensityPlots to make the zero white

We are trying to plot a density plot using the TemperetarueMap colour scheme. However, we don't seem to be able to make the white colour correspond to the value zero of the function we are plotting. ...
230 views

### How to use a Butterworth bandpass filter to generate a chirped signal [duplicate]

As there is no ChirpSignal function in Mathematica, I wrote a simple code to generate a sinusoid with a frequency that changes continuously from frequency ...
170 views

### C compiler error: the no library could be generated error

I have windows 8, Mathematica 9, and I've just installed Microsoft Visual Studio 2013 with update 3. I'm try to run Compile with the option ...
139 views

### Why the function cannot achieve the expected result?

Today, I write a toy code (Framed the prime in a list) to practice Mathematica programming ,which as shown below: Trail 1: ...
128 views

### How can I plot a list of 1-D data along the x-axis?

I would like to know how to create a graph from the following data: ...
353 views

### Pull out scalars from NonCommutativeMultiply in commutator of SU2 spin algebra

I am trying to work on spin chains in Mathematica. That is, N spin-1/2 on a one-dimensional lattice with periodic boundary condition (N+1=1). I need therefore the SU2 spin algebra $S_z, S_+, S_-$ with ...
275 views

### Uniform distribution on unit circle

I need a uniform distribution on the unit circle (x; y) : x^2 + y^2 <= 1 with the density f(x) = (2/Pi) Sqrt[1-x^2] ...
189 views

### How find solve the equation complex conjugate? [closed]

Tried solving it with every function I know but couldn't z*=z^2
129 views

### How to select states with equal times

Can anyone show me how to select the states that have equal times-dates. For example, i have two time series. First that have 10 observations, say from 2014/10/1 to 2014/10/10, and second that have 7 ...
50 views

### simplifying the range of two definite integrals

Today, I tried to obtain the solution of the following equation, sol = DSolve[ {m v'[t] + \[Gamma] v[t] == \[Xi][t] , v[0] == v0}, v[t], t] The solution, of ...
54 views

### How to increase the font size in PlotMakers

When I use PlotMarkers -> {\[FilledCircle], 40} in ListPlot I get something like this: How can I increase the font size of ...
111 views

### Strange integration

Bug introduced in 9.0 or earlier and fixed in 10.1 Note: Beginning with V10.1, this integral returns unevaluated but without error messages. I tried to evaluate this line ...
149 views

### GroupBy and MaximalBy to create a new Dataset

I'm looking for a neater way to achieve this, which to me looks awkward and suggests that I am missing something... Given a Dataset... ...
171 views

### Replace list of symbols in an expression

I have an expression: exp = a+b+c and a list containing all the symbols of my expression: syms = {a,b,c} and I would like ...
95 views

### Conditional combining of nested lists

I have two nested lists like those {{a,A},{b,B},{c,C}...{z,Z}} {{a,1},{c,2}...{t,12}}. I want to combine them to get a new list that looks like this ...
123 views

90 views

### Calculating eigensystem of a matrix containing very small numbers [duplicate]

I'm dealing with a matrix containing very small numbers like 10^(-370). When I compute the eigensystem of my matrix, it takes too much time, though the matrix size is not large. Can anyone explain ...
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290 views

### What is the right place for user-defined init.m?

What is the right folder to put a file init.m which will be run after all other init.m files applied by the various components of Mathematica have done their job? ...
531 views

### Change string date/time to be understandable for mathematica

I'm trying to convert a string of a data and time to be understandable for mathematica (I want to make time related plots). However, I can get my head around how to do this. For example: ...
76 views

### Generate a sequence of names such as a1, a2, a3 [duplicate]

How do I generate the sequency {disp1, disp2, disp3, ...}? I tried the following but it didn't give me what I expected: ...