If you own an iPod Touch, iPhone or an iPad then you really should download this awesome free app called Quick Graph. It's an easy to use app that plots graphs of equations that you input. You can swipe your finger across the graph to move around it and pinch to zoom in and out. I'm going to experiment with using this in a few of my lessons this year.
Click here to download Quick Graph for free from the iTunes App Store
Challenge:
Plot the graphs of
y = x
y = 2x
y = 3x
y = 4x
How does the number in front of the x (which we call the coefficient) change the graph?
Now plot the graphs of
y = 2x
y = 2x + 3
y = 2x + 5
y = 2x - 4
How does the number after the x (which we call the constant term) change the graph? What is the link between this number and the y axis?