ECON 107 Principles of Microeconomics Week 12 NOVEMBER

ECON 107 Principles of Microeconomics Week 12 NOVEMBER 2013 Chapter-11 1 12 w/11/2013 Dr. Mazharul Islam

11 12 w/11/2013 OUTPUT AND COSTS Dr. Mazharul Islam

3 Lesson Objectives Examine what items are included in a firm’s costs of production. Analyze the link between a firm’s production process and its total costs. Learn the meaning of average total cost and marginal cost and how they are related. Consider the shape of a typical firm’s cost curves. 12 w/11/2013 Dr. Mazharul Islam

4 Short-Run Cost A firm’s total cost (TC) is the cost of all resources used. Costs of production may be divided into fixed costs and variable costs Total fixed cost (TFC) is the cost of the firm’s fixed inputs. Fixed costs do not change with output. 12 w/11/2013 Dr. Mazharul Islam

5 Short-Run Cost Total variable cost (TVC) is the cost of the firm’s variable inputs. Variable costs do change with output. Total cost equals total fixed cost plus total variable cost. That is: TC = TFC + TVC 12 w/11/2013 Dr. Mazharul Islam

Costs (dollars) 6 Combining TVC With TFC to get Total Cost 12 w/11/2013 TC TVC Fixed Cost Variable Cost TFC Quantity Dr. Mazharul Islam

7 Figure shows a firm’s total cost curves. Total fixed cost is the same at each output level. Total variable cost increases as output increases. Total cost, which is the sum of TFC and TVC also increases as output increases. 12 w/11/2013 Dr. Mazharul Islam

8 Short-Run Cost Total Fixed Costs = Total costs – Total Variable costs (TFC = TC – TVC) Average fixed cost (AFC) is total fixed cost per unit of Total output. Fixed Costs Average Fixed Costs (AFC) = Total Quantity (output) 12 w/11/2013 Dr. Mazharul Islam

9 Short-Run Cost Total Variable Costs = Total costs – Total Variable costs (TVC = TC – TFC) Average variable cost (AVC) is total variable cost per unit of output. Average Variable Costs Total Variable (AVC) = Quantity Costs Total (output) 12 w/11/2013 Dr. Mazharul Islam

10 Short-Run Cost Total Cost = Total Fixed + Variable Co Average total cost (ATC) is total cost per unit of output. Total Costs Average Total Cost (ATC) = Total Quantity (output) OR ATC = AFC + AVC Change in Total Costs Marginal Cost (MC) = Change in Quantity 12 w/11/2013 Dr. Mazharul Islam

11 Short-Run Cost Figure shows AFC and, AVCcurves. The AFC curve shows that average fixed cost falls as output increases. The AVC curve is U-shaped. As output increases, average variable cost falls to a minimum and then increases. 12 w/11/2013 Dr. Mazharul Islam

12 Short-Run Cost The ATC curve is also U-shaped. The MC curve is very special. The outputs over which AVC is falling, MC is below AVC. The outputs over which AVC is rising, MC is above AVC. The output at which AVC is at the minimum, MC equals AVC. 12 w/11/2013 Dr. Mazharul Islam

13 Short-Run Cost Similarly, the outputs over which ATC is falling, MC is below ATC. The outputs over which ATC is rising, MC is above ATC. At the minimum ATC, MC equals ATC. 12 w/11/2013 Dr. Mazharul Islam

14 Short-Run Cost Why AVC Curve Is U-Shaped The AVC curve is U-shaped because: Initially, marginal product exceeds average product, which brings rising average product and falling AVC. Eventually, marginal product falls below average product, which brings falling average product and rising AVC. The ATC curve is U-shaped for the same reasons. In addition, ATC falls at low output levels because AFC is falling steeply. 12 w/11/2013 Dr. Mazharul Islam

15 Short-Run Cost Curves and Product Curves The shapes of a firm’s cost curves are determined by the technology it uses: < MC is at its minimum at the same output level at which marginal product is at its maximum. < When marginal product is rising, marginal cost is falling. < AVC is at its minimum at the same output level at which average product is at its maximum. < When average product is rising, average variable cost is falling. 12 w/11/2013 Dr. Mazharul Islam

Short-Run Cost 16 Figure 11. 6 shows these relationships. 12 w/11/2013 Dr. Mazharul Islam

17 Short-Run Cost Shifts in Cost Curves The position of a firm’s cost curves depend on two factors: < Technology < Prices of factors of production 12 w/11/2013 Dr. Mazharul Islam

18 Short-Run Cost Technology Technological change influences both the productivity curves and the cost curves. An increase in productivity shifts the average and marginal product curves upward and the average and marginal cost curves downward. If a technological advance brings more capital and less labor into use, fixed costs increase and variable costs decrease. In this case, average total cost increases at low output levels and decreases at high output levels. 12 w/11/2013 Dr. Mazharul Islam

19 Short-Run Cost Prices of Factors of Production An increase in the price of a factor of production increases costs and shifts the cost curves. An increase in a fixed cost shifts the total cost (TC ) and average total cost (ATC ) curves upward but does not shift the marginal cost (MC ) curve. An increase in a variable cost shifts the total cost (TC ), average total cost (ATC ), and marginal cost (MC ) curves upward. 12 w/11/2013 Dr. Mazharul Islam

20 Now it’s over for today. Do you have any question? 5 w/9/2013 Dr. Mazharul Islam