Reputation
57,035
Next tag badge:
139/100 score
18/20 answers
Badges
2 90 227
Newest
 bugs
Impact
~763k people reached

17h
comment FullSimplify not giving me a physically useful answer for Mott scattering
I think you want this: With[{A=1/137,B=1,p=100},NIntegrate[\[Pi] A^2 (1-(B^2) (Sin[x/2])^2) (Sin[x])/(2 (p^2) (B^2) (Sin[x/2])^4),{z,0,750},{x,ArcTan[(600-z),155],ArcTan[(100-z),155]}]]/700 I.e., use NIntegrate and follow the advice of @rcollyer. Note the order of integration variables (outermost first).
19h
comment Simplifying expression with non-commutating entries
@k_v If $[a,b]=0$, it follows that $[a,b^n]=[a^n,b]=0$, so this is not an issue.
19h
comment How to solve time dependent coupled differential equations using Floquet method?
You're missing a Dot in the differential equation. What have you tried?
21h
comment Pull out scalars from NonCommutativeMultiply in commutator of SU2 spin algebra
Yes, with those huge matrices it made a big difference to avoid the LinearSolve step. Fortunately, there is this orthogonality relation between Pauli matrices that makes that possible.
21h
comment Pauli matrices — simplify expressions without printing out the raw matrix
@daveboden Thanks, it's always good to see different approaches.
Jun
26
comment Does Mathematica have a built-in tool that allows one to operate on both sides of an equation?
Or eqn=3x+8==16; Map[1/16*#&,eqn], or Distribute[1/16 eqn,Equal]
Jun
25
comment Defining symbol shortcuts in the Front End
I noticed that in version 10.1 the command OptionValue[Options[EvaluationNotebook[]],InputAliases] does not work in a new notebook. I'll write a new answer with my template code for this.
Jun
25
comment Using Simplify on a consistent system returns False
@SjoerdC.deVries I just added the bugs tag since people seem to agree.
Jun
25
comment Using Simplify on a consistent system returns False
@Dr.WolfgangHintze I just restored version 5.2 and can confirm that Simplify leaves the expression unchanged there (on Mac OS X). This seems to indicate that the bugs tag is warranted here, and it should be reported to Wolfram.
Jun
25
comment Using Simplify on a consistent system returns False
@Dr.WolfgangHintze Very interesting. Now I regret that I deleted version 5.2 just a few weeks ago...
Jun
25
comment Using Simplify on a consistent system returns False
The same happens in version 8. And it also happens with Simplify[x^2==-1||y^2==-1], as if the variables are inexplicably assumed to be real. I agree this shouldn't happen.
Jun
23
comment Where can I find books about how to use Mathematica solving practical problems?
Specifically, you may want to have a look at these books which are classics. Unfortunately, they have never been updated beyond version 5.1. I don't know if I can write an answer, though - the question is very broad. One thing Trott writes in one of his books: "Mathematica ... ages quickly in the sense that in the timescale $10^{1.\text{small integer}}$, a new version will likely be available."
Jun
23
comment How to define an expression which is differently evaluated in calculations and printed
I've done this a couple of times, and maybe these examples help explain the general procedure: How to make traditional output for derivatives, Can I enter the traditional form for Binomial as input in an expression?. If those answers are what you want, I could repeat a summary of the necessary steps and write it as an answer. That could also address what @Kuba is looking for in his comment.
Jun
23
comment Adds a rug representation to plot
@Kattern OK - I guess I cut off the plot range too soon - but it was only meant as a proof of concept...
Jun
23
comment Adds a rug representation to plot
@Kattern OK, I'll add that, too. The heatMap function I was using for convenience can probably be trimmed down and adapted to this particular task some more.
Jun
23
comment Adds a rug representation to plot
What I'm trying to say is that a SmoothDensityHistogram would be a more informative replacement for the "rug" because the superficial simplicity of the rug leads to an ambiguous, less accurate, visual representation of the information that it's supposed to convey.
Jun
22
comment How can I draw a box with moving particles inside and a hole in one side?
Related:Creating an animation illustrating the time-evolution of a pre-computed orbit
Jun
22
comment Adds a rug representation to plot
Closely related: One-dimensional heatmap
Jun
22
comment Any solution to transfer data between Python and Mathematica
Good to see that it worked for you.
Jun
21
comment How to elegantly map multiple functions over a matrix?
@gwr Thanks - I guess one can recognize that Outer is tailored for this scenario, from the fact that no # and & appears in this code...