I'm really confused about how I'd tackle this.
I have an equation, $TC(Q) = 100Q + 20Q^2 + 3Q^3$.
And I'm trying to find where the economies of scale, diseconomies of scale and constant return to scale occurs.
My instinct would be to take the derivative of that function, and then set it to 0, and then see what the values to the left and right of 0 are which would be the slope and allow me to see depending on whether or not they're positive or negative whether it's an economy or diseconomy of scale.
Is this along the right road?