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6:17 AM
I wonder about Mma license pricing. My annual license renewal price seems to differ from listed annual price on the website by about 15% (and that's not taxes)...
 
 
6 hours later…
12:44 PM
@xzczd I just gave some feedback on the resource functions doc page. Seems fixable
 
dtn
12:55 PM
I was busy with numerical differentiation of functions and came across the following.
Remove[f, n, h];

n = 4;

ddddf = 1/h^n Sum[(-1)^(k + n) Binomial[n, k] f[x + k h], {k, 0, n}];

h = 0.0001;

f[x_] := 1/10 Sin[3 x] Exp[-x] x;

Plot[{f[x], ddddf, Evaluate[D[f[x], {x, n}]]}, {x, 0, 5},
PlotRange -> All]
That is for h=0.0001. I guess that this may be due to the step with the accuracy of the calculations, but the deep essence of the phenomenon is unknown to me. Can someone please explain this.
For high-order approximation of derivative I use this formula:
 
@JasonB. Happy to hear that! Hope it can be fixed soon.
 

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