北京大学：《微观经济学》Chapter Twenty-One Cost Curves 成本曲线

Chapter Twenty-One Cost Curves 成本曲线

Chapter Twenty-One Cost Curves 成本曲线

Structure Types of cost curves Fixed variable and total cost functions Average fixed, average variable and average cost functions Marginal cost functions Marginal and variable cost functions Marginal and average cost functions Short run and long run cost curves

Structure Types of cost curves – Fixed, variable and total cost functions – Average fixed, average variable and average cost functions Marginal cost functions Marginal and variable cost functions Marginal and average cost functions Short run and long run cost curves

Types of Cost Curves A tota| cost curve(总成本曲线)is the graph of a firm's total cost function A variab| e cost curve(可变成本曲线 is the graph of a firm's variable cost function An average total cost curve(平均成 本曲线) is the graph of a firm's average total cost function

Types of Cost Curves A total cost curve （总成本曲线）is the graph of a firm’s total cost function. A variable cost curve （可变成本曲线 ）is the graph of a firm’s variable cost function. An average total cost curve （平均成 本曲线）is the graph of a firm’s average total cost function

Types of Cost Curves An average variable cost curve (1 均可变成本曲线) is the graph of a firm's average variable cost function An average fixed cost curve(平均固 定成本曲线) is the graph of a firn’s average fixed cost function A marginal cost curve(边际成本曲线 is the graph of a firm's marginal cost function

Types of Cost Curves An average variable cost curve （平 均可变成本曲线）is the graph of a firm’s average variable cost function. An average fixed cost curve （平均固 定成本曲线）is the graph of a firm’s average fixed cost function. A marginal cost curve （边际成本曲线 ）is the graph of a firm’s marginal cost function

Types of Cost Curves How are these cost curves related to each other? How are a firms long-run and short run cost curves related?

Types of Cost Curves How are these cost curves related to each other? How are a firm’s long-run and short￾run cost curves related?

Fixed. Variable total cost functions F is the total cost to a firm of its short- run fixed inputs(固定投入).F,the firm's fixed cost, does not vary with the firm' s output level Cly) is the total cost to a firm of its variable inputs(可变投入)when producing y output units. Cyy)is the firm's variable cost function Cyy) depends upon the levels of the fixed inputs

Fixed, Variable & Total Cost Functions F is the total cost to a firm of its short￾run fixed inputs （固定投入）. F, the firm’s fixed cost, does not vary with the firm’s output level. cv (y) is the total cost to a firm of its variable inputs （可变投入）when producing y output units. cv (y) is the firm’s variable cost function. cv (y) depends upon the levels of the fixed inputs

Fixed. Variable Total cost functions cly)is the total cost of all inputs, fixed and variable, when producing y output units. cly)is the firm's total cost function c(y)=F+Cy(y)

Fixed, Variable & Total Cost Functions c(y) is the total cost of all inputs, fixed and variable, when producing y output units. c(y) is the firm’s total cost function; c(y) = F + cv (y)

y

y $ F

Cyy) y

y $ c v (y)

Cyy) y

y $ Fcv (y)