STACK - rational and negative powers (2)

STACK - rational and negative powers (2)

by Martin Kreh -
Number of replies: 2

This question can be seen as a follow-up on this. In a question where \(\frac{1}{x^6}\) is the correct answer, I want to allow both \(\frac{1}{x^6}\) and \(x^{-6}\) as correct answers. If I put both of them in the prt as correct answers (I am using the EqualComAss test), the answer \(x^{-6}\) will not be accepted as correct. The same happens with \(x^{\frac{1}{2}}\) and \(\sqrt{x}\). What do I have to do such that in this two cases both of the anwers are accepted as correct?

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In reply to Martin Kreh

Re: STACK - rational and negative powers (2)

by Christopher Sangwin -
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My guess here is that you have not switched off simplification in the potential response tree.

If "Auto-simplify" is "yes" (the default) then x^-6 will be simplified to 1/x^6 automatically, so the comparison will not be what you expect!

You can debug what is really being tested in the Question Test Page.  You can see results of the tests in the screen shot. 

ATEqualComAss(1/x^6, x^-6) = [0, "ATEqualComAss: (AlgEquiv:true)."];
ATEqualComAss(1/x^6, 1/x^6) = [1, ""];
Actually you can type in the following into the Maxima "sandbox", and check what tests do offline if this helps as well.
ATEqualComAss(1/x^6, x^-6)

If you reaname the "question" files from .txt to .xml you should be able to import the question.  If you still can't figure out what is wrong with your question, email me a copy and I'll take a look.

Chris


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In reply to Christopher Sangwin

Re: STACK - rational and negative powers (2)

by Martin Kreh -

Yes, the problem was that the setting for "Auto-simplify" was "yes". Turning it off solved the problem, thank you.

Martin