SeriesCoefficient returns unevaluated

Question

    SeriesCoefficient[x^m, {x, 0, p}]

This gives back the same thing. I tried Assumptions, FullSimplify etc. I keep getting back the same thing. The answer is clearly KroneckerDelta[p,m]

it seems to work only when you give it a numerical value for m. as in SeriesCoefficient[x^4,{x,0,p}] then it gives Piecewise[{{1, p == 4}}, 0] — Nasser, Feb 26 '18 at 09:51

score 2 · Answer 1 · answered Feb 26 '18 at 10:00

2

With Assumptions you get

SeriesCoefficient[x^m, {x, 0, p},Assumptions -> Element[{p, m}, Integers]]
(* Piecewise[{{1, m == p}}, 0] *)

answered Feb 26 '18 at 10:00

Ulrich Neumann

2

That is strange, because I tried this also when I looked at it. But It still returned unevaluated. I tried Reals also. which version are you using? I am using 11.2 on windows. – Nasser Feb 26 '18 at 10:04
Thanks to Ulrich. Now it works. – Quasar Supernova Feb 26 '18 at 10:05
My version is 11.0.1/Windows – Ulrich Neumann Feb 26 '18 at 10:05
3

may be then it is a bug? Why does it work on 11.0.1 and not on 11.2? May be if confirmed, this should be reported to WRI. – Nasser Feb 26 '18 at 10:11
I also see no evaluation on 11.2; I think it's a bug/regression. – Pillsy Feb 26 '18 at 16:53

1 Answers1