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Transformation of graphs

January 17, 2016

I always like it when I find a way to answer a question that I hadn’t previously thought of. Here’s one from a recent mock exam my year 12s took.

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Fairly straightforward I think. I would substitute (x-2) in for all the xs, like this:

transforming graphs

Maybe you’d do the same. However, here’s what one of my students did:

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Factorising first makes it quite a bit easier in this case. It may well be that you’re reading this thinking “Well, yeah. Of course!” but it didn’t occur to me and is a nice reminder of how we can probably all continue improving and learning ‘new’ approaches.

There is a question of when exactly it this approach is going to be easier. Sometimes (or often even), I think it’s going to still lead to  pair of brackets that need to be multiplied out and may be more difficult than the way I did it. I’ll have to ask this student if she’d considered that before factorising but even if she didn’t, I’m still impressed with her flexibility of approach.

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From → Maths, Teaching

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