barrycarter
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 Jan19 awarded Teacher Dec14 asked Mathematica can't solve simple force-generated-by-cuboidal-planet integral? Dec1 comment Lists for built-in functions that can work without brackets Pi and E and EulerGamma though you could argue these are constants (and boringly return themselves). I'd look for functions that take no arguments, though I can't imagine there are many interesting ones that aren't constants. Nov30 awarded Curious Nov29 asked “Power series” in Cos[n*x] for X coordinate of planetary ellipse Nov6 accepted Integrate over piecewise function defined using /; Nov6 comment Integrate over piecewise function defined using /; Thank you!!!!!! Nov6 comment Integrate over piecewise function defined using /; OK, is there any "magic" way to convert one form to the other? (ie, a way that requires minimal effort on my part?) Nov6 comment Integrate over piecewise function defined using /; @BobHanlon Unfortunately won't work if the integration contains variables other than x. Nov6 asked Integrate over piecewise function defined using /; Nov4 comment The speed of Sum[] varies strangely I did your Sums on my Mathematica in a different order and got qualitatively different results. The 10^6 took a lot longer, but the 10^7 took even longer. Then, 10^8 was very quick. When using Mathematica for timing, be sure to clear caches/etc to make sure you're not getting inaccurate times. Restarting Mathematica each time might also make the timing more accurate. Nov1 comment Curve fitting of a list FindSequenceFunction? Oct30 comment Using FindFit to return a list of possible best fits You could try using Method->NMinimize to get a different (usually better) fit. You could try tweaking the other parameters for different types of fits (eg, different NormFunctions, perhaps straight line distance instead of y distance) Oct30 comment Can not understand the code to plot Fourier Series approximation of the line I didn't see an In[9] on that page? It skips from In[8] to In[11] I believe? Oct30 comment Why can't I import a file in the init.m file? I get "Import::infer: Cannot infer format of file table.csv." when I do it. Try it without the semicolon to see if spits out an error. Bizarrely, this works fine if I do it after Mathematica loads. Oct30 comment Series expansion of InterpolatingFunction obtained from NDSolve Do y''[t] /. First@NDSolve[{y'[t] == y[t], y[0] == 1}, y''[t], {t, 0, 1}] and then Plot[%,{t,0,1}] and the result looks correctish (I think your t->0 is being evaluated at the wrong place)? I agree with @Eckhard too: try FindSequenceFunction or something maybe. OK, I see what happens. The function is 4+ at t=0 (PlotRange->All helped) but it becomes correct even an infinitesimal distance from t=0. That's sort of reasonable since t=0 is a boundary. Oct30 comment Series expansion of InterpolatingFunction obtained from NDSolve NDSolve[{y'[t] == y[t], y[0] == 1}, y'[t], {t, 0, 1}] will solve for y'[t]. By solving for arbitrary derivatives, you might be able to use Taylor series expansion directly? Oct26 comment How to build a constant Graphics object Would //InputForm help? Save plot1 as its input form? BTW, do you mean Plot3D instead of Plot above? Oct23 comment Define a Recurrence Table involving other tables If the rewritten code's not private, could you cut/paste it. I'd like to run it directly and see what's going on? Oct20 answered Define a Recurrence Table involving other tables