Given the Following Demand Function

Given the following demand function:
Q = 2.0 P^-1.33 Y^2.0 A^.50
where Q = quantity demanded (thousands of units)
P = price ($/unit)
Y = disposable income per capita ($ thousands)
A = advertising expenditures ($ thousands)

determine the following when P = $2/unit, Y = $8 (i.e., $8000), and A = $25 (i.e., $25,000)

(a) Price elasticity of demand
(b) The approximate percentage increase in demand if disposable income percentage increases by 3%.
(c) The approximate percentage increase in demand if advertising expenditures are increased by 5 percent.