In: Economics
The production function of a competitive firm is given by f(x1, x2) = x1^1/3 (x2 − 1)^1/3 The prices of inputs are w1 = w2 = 1. (a) Compute the firm’s cost function c(y). (b) Compute the marginal and the average cost functions of the firm. (c) Compute the firm’s supply S(p). What is the smallest price at which the firm will produce? 2 (d) Suppose that in the short run, factor 2 is fixed at ¯x2 = 28. Compute the short run total, average and marginal cost functions and the firm’s supply. What is the smallest price at which the firm will produce? (e) Suppose that the market demand is given by D(p) = 240/p. Compute, for the long run, the equilibrium: price, output of each firm, and number of firms. (The output of a firm does not have to be an integer number, but the number of firms must be an integer.)
The production function is given as
. The cost of production is
or
.
(a) The MRTS would be as
or
or
. The optimal input combination would be where
or
or
.
Putting this in the production function, we have
or
or
or
, and since
, we have
or
. These are the conditional input demand. Putting these in the cost
of production, we have the cost function as
or
or
.
(b) The marginal cost would be as
or
or
. The average cost would be as
ro
or
.
(c) The VC would be as
, and the AVC would be
. The supply curve for the firm would be where MC=p, sucht that
MC>AVC. As can be verified, since
, we have MC>AVC for all y>0. The supply function would be as
or
. The minimum price at which the firm can produce would be the
minimum of AVC, which is where MC=AVC. We have
and
, and MC=AVC would only be where y=0. At y=0, we have the minimum
of AVC where
. Hence, the firm would produce for p>0.
(d) For x2 fixed at 28 in the short run, we
have the production function as
or
or
, and we have
or
as the short run conditional input demand. The short run total
cost function would be as
or
.
The marginal cost would be as
, and the average cost would be as
. The short run supply would be where MC=p, provided MC>AVC. We
have AVC as
, and MC>AVC for all y>0. Hence, the short run supply would
be as
or
or
. The smallest price would be where MC=AVC, and since
and
, we have MC=AVC where y=0. Hence, the minimum AVC would be
, meaning that for p>0, the firm produces.
(e) In the long run, the firms produces at
minimum of AC, which would be where
or
or
or
or
or
, and the minimum of AC would hence be
. Hence, the long run equilibrium price would be p=3. The output of
each firm would be y=1.
The long run quantity demanded would be
units. For each firm produces y units, we have the total quantity
supplied would be
, and since quantity supplied would be equal to quantity demanded,
we have
or
, ie there would be 80 firms.