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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closed as off-topic by Henrik Schumacher, rhermans, m_goldberg, Michael E2, MarcoB Jul 25 '18 at 3:27

This question appears to be off-topic. The users who voted to close gave this specific reason:

  • "This question arises due to a simple mistake such as a trivial syntax error, incorrect capitalization, spelling mistake, or other typographical error and is unlikely to help any future visitors, or else it is easily found in the documentation." – Henrik Schumacher, rhermans, m_goldberg, Michael E2, MarcoB
If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ 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

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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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