Introduction to Inverse Functions
Introduction to Inverse Functions
Inverse functions are created by reflecting the original function over the line y=x.  That is, the outputs are now the inputs, and the inputs are now the outputs.  
View the point D and E.  The green point, D, is a point on the original function, (x, f(x)).  The blue point, E, is defined to be (f(x),x).  Thus, it is a point on the inverse function.
Drag the green point along the function, f(x), to view the inverse function.
Now change the function f(x)=x^2+2.  (That is, do not restrict the domain.)  Drag the green point along f(x).  What do you notice?  Is the graph made by the blue point a function?