## Tuesday, 4 August 2015

### Match my Exponential Graph

Inspired by Michael Fenton's fantastic looking "Match my Line" and "Match my Parabola" resources I have created a similar activity to explore exponential functions using Desmos's new activity builder. I haven't actually road tested this yet but when I heard about the release of Desmos's activity builder I couldn't resist giving it a go and thought this would be a great way for students to explore basic exponential functions.

Students have to come up with an equation in the form $y=a^x$ that goes through the coordinate points given in each challenge, there are also a couple of open questions thrown in. They should login at student.desmos.com using the class code that you as the teacher will be assigned to distribute. As the teacher you can then see students graphs and answers and share them for discussion (e.g. the misconception in fifth screen here).

Whilst solving each challenge students can experiment by plotting different graphs, this experimentation is the key to learning through this type of activity; students can quickly identify their own misconceptions and experiment to correct them.

My only concern with these 'Match my ... Tasks' is that students may use sliders to solve the problems very quickly without giving them much thought. Whilst sliders are a powerful tool for visualizing the effect of changing parameters I would like to have the the ability to disable them in certain challenges - I think the cycle of thinking about an equation, manually typing it in, checking its graph and then rethinking the answer is important to allow thinking time for students to develop new concepts. This thinking time may be avoided if the problems are solved quickly using sliders. Hopefully Desmos will make this possible in the future but until then I would encourage students not to use sliders for this particular activity or only a last resort.

I will definitely be trying this out at the first opportunity next year. This activity was really quick and easy to make - why not try creating one yourself ? Let me know how you get on.