Marginals for the exponential function and log function from Excel models y = de" then y' = abe The marginal sales in week x is y'. Ex: Assume y =14000e then y' =14000(.002)e"?* = 28e" and in week 50, the rate of change in sales is y' = 28023 =28el =30.94 . Y=alnx+b then y'= a X The marginal sales in week x is y'. 1600 1600 Ex: y=1600Inx+9000 then y' = and in week 50, the rate of change in sales is y' = = 32 . X 50 Note: Also compute the marginal for models in other weeks to see the rates of change then.