It is important that everyone understand functions and their graphs in order to communicate trends or advance beyond basic mathematics. This book has several interactive applets that illustrate functions. It starts with set of common functions where the independent, , value can be adjusted and arrows show how a dependent, , value can be obtained. Generally a different function can be chosen by clicking a next button or a user function can be entered. The questions focus on the domain (all possible values ) and range ( all possible values ). It would help, but is not necessary, that you know the definitions of the basic trigonometric, exponential and logarithmic functions.
The applets illustrate basic functions, piecewise functions, graphs that are not functions, addition, subtraction , multiplication and division of functions, shifting and scaling functions, and composite functions. These are all concepts that should be understood for the study of calculus.
You could have hours of enjoyment playing with different functions in this book.