1) Revenue = Production * Price = (10-.001x)x
2) To Max R, take derivative of R wrt x and set =0. Find x = 5000 units to max R
3) Profit (Income) I= Revenue-Cost = (10-.001x)x-1000-2x=8x-.001x2-1000
4) To Max I, take derivative of I wrt x and set =0. Find x=4000 units to max I
5) Including tax, cost = 1000+4x
6) New I = (10-.001x)x-1000-4x
7) To Max I, take derivative of I wrt x and set=0. Find x= 3000