Monday, February 11, 2013

Function Machines

It's been awhile and I'm so far behind in my blogging.  So here we go...

Before winter break we talked about functions.  For many of my students this year is the first time they have seen anything Algebra so we keep it pretty simple.  I started off talking about a Function Machine, I like to use a pop machine as my class example.  We talk about how if we push the Pepsi button we should get a Pepsi out, but if we push the Pepsi button and a Mt. Dew pops out then our machine doesn't function properly.  I went into how for every input you have exactly one output.  Many of them understood after the pop machine example.

I gave students this chart to put in their ISN.  The top box was Graphing Functions From a Table.  I taught them how to create an XY table and how the values create points that we put onto a graph.  Then we found a few extra points that were on the line but not in our table.

We then moved onto Graphing a Function.  I gave them y = 2x - 1 and we decided we would use the values -1, 0, 1, and 2 for X.  The students plugged the values into the equation and solved for Y.  Then graphed the points.  I again made them find some extra points that were on the line but not in our graph.

Doing the extra points helped my students see that the line does not stop just because we ran out of points to graph.

We then moved on to their practice.

We defined the terms Domain and Range, each one getting their own color.  After we defined them we went back to the left side of our notebook and highlighted which values represented the Domain, and which represented the Range.

I then gave them two functions which they had to give values for x and plug them in to find the y.  After they were done they had to graph their points and then find a few that were not in their chart.  Again they lighted the Domain and Range Values.

As an activity I asked my students to create their own function machine.  It gave them time to be creative, though this class is not at all creative so many of them just drew boxes as their machines.

They were asked to create an equation, but not draw it on their page.  They had to create the XY Table, filling in both sets of values.  The students then went around and had to figure out what everyones equation was.

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