My professor asked to take the derivative of profit for fun so I just wanted to check if my answer was right.

Question

profit=PQ(p,a)-c(q(a))-a

dΠ/dQ = -2bQ + (a-c) ≡ 0.
Thus, -2bQ = -(a-c) and Q = (a-c)/2b.

Answer 1

Its kinda hard to tell, but something in your answer looks odd. There is nothing in your profit equation that would produce the term "-2bQ"

Answer 2

do you have any pointers on how i could fix this or maybe what is the right way of taking the derivative??