ANALYSIS OF COSTS

SHORT-RUN COST FUNCTION

TOTAL COST TC = FC + VC

FIXED COST - stays constant no matter what level of output

VARIABLE COST - vary with the level of output

COST CONCEPTS

Marginal cost = the extra or additional cost of producing 1 extra unit of output

Average cost (unit costs) – concept that enables a firm to dicern whether or not it is making a profit (compared with price or average revenue)

AC can be broken down into two components – AFC and AVC

Average Fixed Cost since total fixed cost is a constant, dividing it by

an increasing output gives a steadily falling

Average Variable Cost VC divided by output

Q

FCAFC

Q

VCAVC

Relationship between AC and MC

if MC is below AC, AC must be falling (the last unit produced costs less than the average of all the earlier units produced č AC including the last unit must be less than the old AC) ,

if MC is above AC, AC must be rising (the last unit costs more than the average of the earlier units, the AC including the last unit must be higher than the old AC),

if MC is just equal to AC čthe last unit costs exactly the same as the average cost of all earlier units (the AC curve is flat).

Short-run cost curves

EUR/QMC

AC

Q

AVC

q*

AFC

THE LINK BETWEEN PRODUCTION AND

COSTS the shape of cost curves is affected strictly by the

shape of production function, which reflects the form of returns čthe U-shaped cost curves are grounded in the law of diminishing returns

the essence of the link between costs and production is simple – for each level of output, firms must choose the least costly combination of inputs

THE LONG-RUN COST CURVE

the long-run cost curves depends on production function also – therefore, depends on the returns to scale

the long-run average cost (LAC) curve is called „envelope curve“, because it wraps around the outside of all the short-run curves

LMC can be derived from the LAC – also goes through the minimum point of the LAC and has a gentler slope than the short-run SMC at the minimum point

The Least-cost Rule

whatever the level of output, the firm should strive to produce that output at the lowest possible cost and thereby have the maximum amount of revenue left over for profits

MPL/ w = MPK/r

Č technological optimum = the level of output with the lowest average cost

Other cost concepts

difference between economic and accounting approach to cost

OPPORTUNITY COST (implicit cost) = implicit return to labor supplied by the owner of a firm

1. Decide, what is the optimal level of output regarding to the technology knowing:

2. Calculate and graphically depict the course of AC, AVC and AFC curves.

3. Calculate and graphically depict the course of FC, VC, MC, AC curves.

4. Explain mistakes in thinking:

a) While the total cost are constantly growing, the average cost must be growing also,

b) It is optimal to produce the amount of production for firm, which corresponds to the intersection of MC an AC from economic point of view,

c) AC tends to decline, as long as the MC are declining.

Q 1 2 3 4 5 6 7

MC 54 20 19 23 49 69 102

Q 0 1 2 3 4 5 6

TC 100 220 240 420 840 1 500 2 400

Q 1 2 3 4 5 6

AVC 21 18 14,6 15,5 22 31,3

AFC 10 5 3,3 2,5 2 1,6