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Nov
6
accepted Integrate over piecewise function defined using /;
Nov
6
comment Integrate over piecewise function defined using /;
Thank you!!!!!!
Nov
6
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?)
Nov
6
comment Integrate over piecewise function defined using /;
@BobHanlon Unfortunately won't work if the integration contains variables other than x.
Nov
6
asked Integrate over piecewise function defined using /;
Nov
4
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.
Nov
1
comment Curve fitting of a list
FindSequenceFunction?
Oct
30
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)
Oct
30
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?
Oct
30
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.
Oct
30
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.
Oct
30
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?
Oct
26
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?
Oct
23
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?
Oct
20
answered Define a Recurrence Table involving other tables
Oct
20
comment Define a Recurrence Table involving other tables
I'd like to take a further look at this: could you provide actual runnable code (using simple functions if you don't want to provide the originals)? In general, you can't use "=" when the right hand side is undefined, so you'd have to compute M, Psi, and Lambda first.
Oct
19
comment Solving 4 variable system of equations
Do you have any additional constraints you could add, such as qIndoor > 0, qOutdoor > 0, etc? Also, try solving the first equation to get qOutdoor as a function of qIndoor, and substitute into the second equation, etc. This piecemeal solution may work better.
Oct
19
comment Define a Recurrence Table involving other tables
Look at the differences between = and :=
Oct
19
comment What is the algorithm behind Mathematicas Reduce in this equation?
NSolve instead of Reduce will work, but it looks like you want an exact answer?
Oct
19
comment Is there a way to stop Export if the file size is too big?
If[StringLength[ExportString[...,...]] > n, ..., ...] wouldn't work? Or would that use up too much memory (ie, it'd use the same amount of memory as it would diskspace)