All Questions

0
votes
0answers
3 views

Multiple dynamic equations for plotting?

Say I have a bunch of equations between variables e.g. a=bcd, d=bc, e=bda and I want to do a plot between any two of them, is there an easier way than just rearranging by hand and then plugging into ...
0
votes
0answers
24 views

Use the trigonometric identities to expand and simplify if possible

Use the trigonometric identities to expand and simplify if possible. A, cos(270∘−θ) B, sin(270∘−θ) C, cos(270∘+θ) Here is my answers, it needs checking. 1. cos(270 - theta) = cos( 180 +90 - ...
312
votes
12answers
58k views

Where can I find examples of good Mathematica programming practice?

I consider myself a pretty good Mathematica programmer, but I'm always looking out for ways to either improve my way of doing things in Mathematica, or to see if there's something nifty that I haven't ...
2
votes
1answer
81 views

How to make hollow octahedron 3-compound?

I would like to remove facets from a graphic - like on the picture below. Link I tried to combine these two graphics: ...
1
vote
0answers
24 views

Interpolating a polynomial for with first and second derivative of points

I am trying to fit a polynomial for switch cutoff which is used in Molecular dynamics. I want a fifth order polynomial with six coefficient $c_0, ...,c_6$ between $r_1<r<r_2$ with these ...
4
votes
2answers
3k views

How to handle NDSolve::ndsz problem (singularity problem)

I have 2 second order differential equations (non-linear). The physics behind them is correct. I verified the equations many times. It is a solid pendulum with a mass-spring at the end of it. Now, ...
-1
votes
1answer
42 views

Help with the plot f(x)=2ln(-0.5x+2)-1

I don't know how to write equation in the notebook. The graph doesn't appear when I tried.
-1
votes
1answer
35 views

How can I graph the polynomial function? [on hold]

There is no explanation for the polynomial function. The equation is f(x)=-2x^2-4x-3.
3
votes
2answers
125 views

Coordinate free differential forms package

I am looking for a package in Mathematica which can handle differential forms in a coordinate free manner. I am aware of several packages which do differential forms, but it seems that for all of them ...
5
votes
1answer
104 views

Obtain polygons describing all intersections of many polygons

I have 6894 polygons describing zones in a state plane (i.e., cartesian) coordinate system. Most are not very complex, and I believe none have holes. A random example is Polygon[{{351633., ...
3
votes
2answers
25 views

How to keep first observation and delete other observations of each group in unbalanced Panel data

I have a huge panel data. I want to create a new data keeping only first observation of each group. How can I achieve it? For illustrative purpose; ...
0
votes
1answer
35 views

Copy files existing in different directories under the same directory

I have many files existing in different directories, I need to copy it under the same directory. Any suggestions?
0
votes
1answer
20 views

Mixture coefficients and Parameter estimation for moving Normal distributions

I am searching for a way to do the following steps below. I am stumped and I have stumped a few profs too. Any help would be appreciated. I would like to import data from, say, excel or a .txt file ...
1
vote
3answers
96 views
+100

Developing a function of two variables from given data

Cross listed from MSE: http://math.stackexchange.com/questions/1029399/developing-a-function-of-two-variables-from-given-data (I believe Mathematica SE is an appropriate place to ask this, as well.) ...
0
votes
1answer
55 views

How to tell Mathematica that certain variables are real/imaginary, integer-valued, etc

I'm trying to expedite some quantum mechanical calculations by running them through Mathematica. Expectation values and stuff like that. When I say, for example, ...
1
vote
0answers
38 views

The use of Evaluate in NDSolve and Plotting the answer [duplicate]

I am having a bit of hard time understanding the use of Evaluate when plotting the output of NDSolve. From the documentation, I enter: ...
0
votes
0answers
27 views

How do I include assignments inside this?

Noobie question, but if I have this: ...
2
votes
2answers
39 views

Default color for Filling in Mathematica 9

The default color scheme for plots in my Mathematica version is ColorData[1]. What about for the Filling option?
0
votes
1answer
37 views

DateListLogLogPlot

The command completion feature in Version 10.0.1.0 shows a command DateListLogLog but there is no documentation and doesn't work. Is this something that is going to be released in the near future and ...
3
votes
1answer
56 views

Coding `While` loops

I am interested in replicating the code in this question on MSE, whose contents I have copied for ease of reading: Pseudocode: Consider that 1 is the starting index of a list 1.  input natural ...
0
votes
1answer
52 views

Make plots of solutions persist

How can the code below be modified so that at allow plots of solutions to persist upon clicking in the slope field. For example, after three clicks, the plots of all three solutions should remain. In ...
8
votes
1answer
117 views
+50

How to use C language functions in Mathematica?

I'm trying to find out the way to use c-functions in Mathematica (I'm using 14 version) on OS X 10.10. For example I've got this lines of code: ...
6
votes
1answer
170 views

How to write Morse code into Plot Dashing?

How can we define a dashing pattern in a plot such that it reads arbitrary text in Morse code? For instance Graphics[{DotDashed, Line[{{0, 0}, {5, 0}}]}] ...
1
vote
1answer
64 views

PlotStyle and Legends

I know only three plot style ...
4
votes
3answers
343 views

Camel hump string split

Given System names of 2 or more characters: systemNames = Names["System`*"] // Select[StringLength[#] > 1 &] ; Is ...
1
vote
1answer
38 views

What extrapolation method does Interpolation use by default?

As far as I can tell, Interpolation uses cubic spline interpolation by default - please correct me if I'm wrong. What does it use for extrapolation outside of the ...
1
vote
1answer
52 views

How to embed a filled Region in a Graphics?

Let for example: regn = RegionDifference[Rectangle[{-2, -2}, {2, 2}], Disk[{0, 0}, 1]]; The only documented way I found to draw a gereric region ...
0
votes
1answer
21 views

Defining an array using this specific rule [on hold]

To a pair of natural numbers $(m,n)$ I would like to associate the $6(m-n+1)\times 2$ array whose rows consist in all pairs $\{x,y\}$ of natural numbers where $m\leq x \leq n$ and $y\in[\lceil x/5 ...
2
votes
0answers
34 views

Fitting an implicit function to data with error bars

I am trying to fit a Brillouin function to the peak intensity of neutron scattering data, for which I have an error bar for each data point. For this the program has to fit a function, for which the ...
7
votes
0answers
57 views

Is plot polluting my context?

Whenever I plot something 3 temporary variables get added to my current context. Example (fresh Kernel): Plot[x, {x, -1, 1}]; Names["Global`*"] Output: ...
3
votes
5answers
88 views

Symbolic versus numeric sum (is there an inconsistency?)

Something seems to have gone awry with the analytic sum (v9.0.1). Here I insert specific values: ...
1
vote
1answer
48 views

Non-linear system of equations with a parameter

I want to solve k*x-(x-y)*y^2==0 and y+(x-y)*y^2-(1-x-y)==0 for -10 < k <10 How ...
0
votes
0answers
58 views

Having difficulty with NDSolve [on hold]

I've entered: NDSolve[{y'[x] == z[x], z'[x] == -y[x], y[0] == 0, z[0] == 1}, {y, z}, {x, 0, Pi}] The code above was copied and pasted from the Mathematic help ...
4
votes
0answers
199 views

What is the algorithm behind Mathematicas Reduce in this equation?

Mathematica can use Reduce to arrive at an answer in this equation ...
15
votes
3answers
683 views

Is it possible to draw really thin lines in Mathematica?

I want to have in Mathematica the same result I have in Python: I have this nice effect simply by using very thin lines. But it seems in Mathematica thickness property has some limit and i just got ...
0
votes
0answers
20 views

Trouble while opening the notebook [on hold]

http://www.physics.umd.edu/courses/CourseWare/EssentialMathematica/Primary%20topics/plotting.nb I have downloaded this notebook and opened it in my wolfram 9 ,but the problem is I am very new at ...
3
votes
2answers
94 views

How to plot a function that is not defined after certain point

I'm plotting a function that I get after numerically integrating over another function. Something like: f[x_,y_]:=NIntegrate[g[x,y,z],{z,0,1}] I know that above ...
0
votes
2answers
46 views

Handling msg for fitting

I have a trivial question: I do Monte Carlo with some curve fitting. Now always when a random run creates a complex fitting solution it should write 1 in a Matrix. How can I handle such msgs in a ...
6
votes
1answer
85 views

Does anyone know a way to draw lines connecting nearest neighbor points in ListPlot[ ]?

I have a two-dimensional mesh that I am visualizing in Mathematica, with ListPlot[]. The mesh looks like this: Any ideas for how to connect all the nearest neighboring points with lines? Thanks, ...
1
vote
3answers
105 views

Applying Reduce[] to a table [duplicate]

I have a table for example: t = Table[k,{k,5}] which returns {1,2,3,4,5} and for every element in this table I want to check when it is $\leq 1 + a$. I ...
9
votes
1answer
165 views

Automatically execute command after save

I want to run some code automatically after saving my notebook. Is there a $ variable or setting for this?
0
votes
1answer
92 views

AstronomicalData not including units?

I like using mathematica to do my physics homework, and AstronomicalData is useful for that, but it doesn't seem to work properly with units. [the question is, at ...
1
vote
1answer
138 views

Combining solar system planets orbits and positions in Graphics3D and Show

I am building an animated model of the solar system, where I would like to display the OrbitPaths of the planets along with their ...
10
votes
2answers
312 views

How to get the distance of Jupiter from the sun?

I am aware of the command AstronomicalData["Jupiter", "Distance"] from which I can get the distance between the earth and Jupiter. Is there any way to use ...
1
vote
1answer
34 views

UnitConvert to Electronvolts converts to Electronvolts/Moles

The question probably is clear from the title. When I want to convert a kinetic energy, that contains the Molar Gas-Constant into Electronvolts I get eV/mol. ...
1
vote
1answer
95 views

Why does LyapunovSolve solve non-standard form?

LyapunovSolve[A,Q] solves the equation $A P + P A^T = Q$ for $P$ whereas the standard form (wikipedia,lecture notes, p.25, linear control systems) of the Lyapunov ...
0
votes
1answer
46 views

How to obtain Padé approximant of $\log(x)$?

Having read this answer on Math.SE, I wanted to try seeing how Padé approximations converge to $\log(x)$. But my first attempt after reading the documentation failed: ...
4
votes
2answers
135 views

Ploting transition dipole moments in a 3D structure

I want to plot the transition dipole moment vectors on their respective position. For example one transition dipole moment have a position vector like R now at this ...

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