Final answer:
The price elasticity of demand for a company's e-reader can be calculated using the derivative of the demand function. At a price of $70, elasticity is -0.7, and at a price of $600, elasticity is -6, indicating inelastic demand at both ends of the price range.
Step-by-step explanation:
The price elasticity of demand (E) is a measure used to show the responsiveness, or elasticity, of the quantity demanded of a good to a change in its price. The general formula is E = (% Change in Quantity Demanded) / (% Change in Price). For the demand function q(p) = 21e−0.01p, the elasticity can be found by using calculus (specifically the derivative of the demand function) and the definition of elasticity:
E = (p/q) * (dq/dp)
We compute dq/dp as the derivative of q(p) with respect to p:
dq/dp = -0.21 e −0.01 p
Now, substitute dq/dp and q(p) into the elasticity formula:
E = (p / (21 e−0.01 p)) * (-0.21 e−0.01 p)
After simplifying, we obtain:
E = -0.01 p
Now, we calculate the elasticity at the two endpoints of given price range:
- E(70) = -0.01 * 70 = -0.7
- E(600) = -0.01 * 600 = -6
These values indicate that at both ends of the price spectrum, the demand for the e-reader is inelastic, since the absolute value of E is less than 1 at p = 70 and greater than 1 at p = 600.