At zero output cost C(Q=0)=100+2*0+3*0^2=100
Revenue = Price*0 units = 0
Profits = Revenues - cost = 0-100= -100 (loss of 100)

With the above cost equation, average total costs (ATC), first decline as output increases, and then begin to rise. Assuming output occurs in whole units, i.e. 1, 2,3,... at what output does the low point of ATC occur and what is the ATC at that output? Show your calculations.