0
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I have coefficient of some expansion:

Workingexpansion = 
  tau/n - (A tau^2)/(27 n^3) - (B tau^3)/(5832 n^5);
CoefficientList[Workingexpansion, tau][[2]]
1/n

I know, that, for example, when i = 2, this coefficient is equal to 1/n, where n is integer. I'd like to check whether the coefficient is zero or not. I found some information here, but, unfortunately it didn't help me.

So this is what I did:

Assuming[
  n ∈ Integers, 
  TrueQ[Simplify[CoefficientList[Workingexpansion, tau][[2]]] != 0]]

And I get False. I don't know how to solve this problem.

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  • $\begingroup$ Me neither. What is Workingexpansion? $\endgroup$ – Henrik Schumacher Jul 23 '18 at 15:06
  • $\begingroup$ tau/n - (A tau^2)/(27 n^3) - (B tau^3)/(5832 n^5) $\endgroup$ – Andrew Kudlis Jul 23 '18 at 15:17
4
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You have to wrap the whole equation with Simplify, otherwise, Assuming cannot become active.

Assuming[
 n ∈ Integers,
 TrueQ[
  Simplify[
   CoefficientList[Workingexpansion, tau][[2]] != 0
   ]
  ]
 ]

True

| improve this answer | |
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  • $\begingroup$ Thank you very much! $\endgroup$ – Andrew Kudlis Jul 23 '18 at 15:39
  • $\begingroup$ You're welcome! $\endgroup$ – Henrik Schumacher Jul 23 '18 at 15:39

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