Is there a command equivalent to that of Coefficient to get the terms of a polynomial which are a power of the variables?
For example:
func[(x^3 + x)^2]
{x^2, x^4, x^6}
Thank you in advance
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1 Answer
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The function MonomialList extracts the monomials, including the overall factor. You can remove the overall factor using FactorTermsList. So, a function to do what you want could be:
Last @* FactorTermsList /@ MonomialList[(x^3+x)^2, x, "NegativeLexicographic"]
{x^2, x^4, x^6}
where I used the non-default order "NegativeLexicographic" to obtain the ordering requested.
answered Apr 2, 2018 at 18:59
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$\begingroup$ What is the name of the "@*" operator? It appears to work here the same as replacing it by "/@". But not in general as in Last@*{{1,x^2},{2,x^4},{1,x^6}}. $\endgroup$ Commented Dec 31, 2018 at 13:45
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$\begingroup$ The "@*" is the in-line form of Composition[.]. $\endgroup$ Commented Feb 22, 2019 at 6:00
CoefficientList[ ]? $\endgroup$func[expr_, x_Symbol] := Cases[Expand[expr], Power[x, _], Infinity] // Union$\endgroup$