Scaling is a little harder to get a handle on. The graph of y = af(x) is a stretched out version of y = f(x) if a > 1. If 0 < a < 1 then the graph is squished down. We can also scale the argument, or independent variable of the function. For example, the graph y = f(ax) has been stretched along the x axis if 0 < a < 1 or squished along the axis if a > 1. Good examples here are the basic trig functions.