Sales growth: The rate of growth G, in thousands of dollars per year, in sales of a certain product is a function of the current sales level s, in thousands of dollars, and the model uses a quadratic...

Sales growth: The rate of growth G, in thousands of dollars per year, in sales of a certain product is a function of the current sales level s, in thousands of dollars, and the model uses a quadratic function:

The model is valid up to a sales level of 4 thousand dollars.

a. Draw a graph of G versus s.

 b. Express using functional notation the rate of growth in sales at a sales level of $2260, and then estimate that value.

c. At what sales level is the rate of growth in sales maximized?