MAT - Paper 2009 - Q5
Flashcards
2021-10-14
For a journey where you get back to the beginning (a “tour”), what must be true about every move made?
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It must have a corresponding opposite; i.e. a forward must have a backward and an up must have a down.
If every move has to have an opposite for a tour, why are $n \times n$ where $n$ is odd not possible?
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There must be an odd total number of moves $n^2$ and it’s impossible for an odd number to come in pairs.
When thinking about traversal questions like this one, what is it good to consider?
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If moves must come in pairs, or there is some relation between current moves and future ones.