Consider the following demand function with a constant slope. Let [math] describe the quantity demanded of the product with respect to price. In this instance [math] will take the form [math] where [math].
Note: The following is a graph of [math] not [math].

(Click on graph to enlarge)

The price elasticity of demand as a function of price is given by the equation [math].
Find [math] and [math] (your answers should be in terms of [math] and [math] ).



Which of the following graphs best matches the elasticity function for the above demand function?

A   B
C   D

(Click on a graph to enlarge it.)