Jens
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 Oct 15 comment Numerical solve question @belisariusisforth OK, I give up any attempt at an explanation. NSolve doesn't even have HoldFirst attribute... Oct 15 comment Numerical solve question @belisariusisforth "Fortunately," NSolve[5 Tan@t + 9 == 0 && 0 <= t <= 2 Pi] does not work here - otherwise I'd be really confused. Oct 15 comment Derivatives of vectors I upvoted this even though your rep counter was just at 4444, and now I messed up that nice number. Sorry for that, I guess. Oct 15 comment Numerical solve question It does work if I do this: NSolve[5 Tan[t]+9==0&&0<=t<2 Pi,t,Complexes]. So you have to allow complex values to get the real solutions. I think that's strange. Oct 14 comment Consistent crash printing from Mathematica 10.2.0 and 10.1.0 in OS X 10.11 El Capitan For completeness, maybe you could note the Case number of the report, too. I do that just to remind myself what has been reported when... the bug reporting with Wolfram is unfortunately very opaque. BTW, my latest PDF export related bug report was sent September 14 and acknowledged as a bug just on October 9 (case 3422830). So patience may be needed... I can't test this one because I'm not on the latest OS X. Oct 14 comment How do I solve for a variable inside a sum but independent of the summation index? The fact that the summation limit and the coefficients aren't numeric makes Mathematica give up, especially since you're asking for a solution over the Reals (which can't be done for the generic coefficients). But if I choose a numeric upper limit for the sum, and remove Reals, it works: Table[c/.First@Solve[0==Sum[(t[i]*m[i]-c*t[i]^2)/s[i]^2,{i,1,n}],c],{n,1,4}]. So you can at least check your manual calculations by inserting specific n. And: never use capitals like N as variable names. Type ?N. Oct 11 comment Edit a Mathematica plot in Illustrator, missing font problem @QuantumDot I stopped using Illustrator when they fully switched to a subscription model, so I can't test any fixes now. But outlining fonts before importing into Illustrator has always been the most fool-proof solution. On Macs, I also have my own solution independent of Mathematica: fontBegone. Oct 11 comment Bifurcation diagram for 1D ising model @BobHanlon Yes, I assumed we only want the nonzero solutions after the bifurcation - this illustrates how to select particular branches if desired. That depends on the goal of the question, which is left open... Oct 7 comment Help me solve this equation; I believe this is a transcendental equation You can also do N[Reduce[{eqn,0<=x<=140},x]]. Sep 28 comment Decreasing computation time for numerical plot Your code is missing several definitions without which the numerical computation can't proceed. Sep 27 comment Why do singularities disappear when performing convolutions with the Dirac Delta function? I was going to answer that you can get the expected result by doing Integrate[DiracDelta[t-a]/(t-a),{t,-m,m}], but that ends up being unconvincing because I can also produce an incorrect error message with a similar command: Integrate[DiracDelta[t-a]/(t-a),{t,2a,3a}]. Here, the singularity is outside the integration domain, so the correct result must be zero. Mathematica version 10 misses this, too. Sep 27 comment Why do singularities disappear when performing convolutions with the Dirac Delta function? @MichaelE2 I agree it's a bug and I added the corresponding tag. The expected result can be see here: Integrate[DiracDelta[t]/t,{t,-Infinity,Infinity}]. Sep 26 comment ContourPlot3D overwrites symbolic values? It's true, one could make these plot functions smarter in the way of recognizing what is meant to be plotted. I've complained about this before, too: e.g., when using Plot with a Table of functions to get several curves at once, the curves all have the same color - whereas they get colored individually if one wraps the Table in Evaluate. This isn't obvious to most new users, and it could be improved. Sep 25 comment How can we make publication-quality PlotMarkers without version 10? Thanks @AlexeyPopkov, I just looked at that answer and I like it... Sep 21 comment How can I write the frame ticks in Scientific Form? I removed the edit because I don't like to have non-working code in my answers. Sep 21 comment How can I write the frame ticks in Scientific Form? @DavidH I don't understand why you edited my answer but still didn't accept it. Also, you added a plot without explanation, not showing the code to produce it. Unless you explain why you did that, I'll probably revert to my original answer because the current form is confusing. Sep 18 comment How does one plot a Möbius Strip? See also the attempted solution in the question Cutting bagels into linked halves. Sep 16 comment Define an operator with the distributive property @Elaeum That case is also easy to take care of. I've added it. The recursion just has to re-examine the new CirclePlus factor individually to see if it can be factored further. Sep 16 comment Define an operator with the distributive property @Karsten7. Indeed, I forgot about that. Now it should be fixed. Sep 15 comment Define an operator with the distributive property @Karsten7. Yes, that's what I intended. It's consistent with the operator precedence rules.