9. A firm faces the following production function:
Q = (41/3)K^(2/3)L^(2/3)
where Q is output, K is capital, and L is labour. Labour and capital can be purchased in competitive markets at a unit cost of £1 and £8 respectively.
In what ratio would the firm wish to employ capital and labour to ensure production at minimum cost in the long run? Solve for the long-run cost function LRC = f(Q).
[10 marks]
(b) Assume the amount of capital in the short run is fixed at K = 8. Solve for the short-run cost function. Explain why long-run costs are smaller than short-run costs almost everywhere, and why they are equal for some values of Q.
[5 marks]
(c) Show that long-run variable costs feature increasing returns to scale, and short-run variable costs feature decreasing returns to scale.