For the price-demand equation p=g(x) =120-0. 4x, how do we find the values of x for which demand is elastic and for which demand is inelastic?
a. Calculate the derivative of the demand function
b. Use the midpoint formula to determine the elasticity of demand
c. Compare the percentage change in quantity demanded to the percentage change in price
d. Calculate the price elasticity of demand using the Arc elasticity formula