可变成本（Variable cost）

假设厂商成本为C(q)=16+4q²。

(1)求出平均成本、固定成本、可变成本、平均可变成本和平均固定成本。(提示:边际成本为MC =8q。)

(2)在图上画出成本、边际成本和平均可变成本曲线。

(3)求出最小化平均成本的产出水平。

(4)当价格在哪一区间时厂商产量为正？

(5)当价格在哪一区间时厂商利润为负？

(6)当价格在哪一区间时厂商利润为正？

Suppose the same firm's cost function is C(q)=16+4q.

a. Find variable cost, fixed cost, average cost average variable cost. and average fixed cost.(Hint: Marginal cast is given by MC =8q. )

b. Show the average cost, marginal cost, and average variable cost curves on a graph.

c. Find the output that minimizes average cost.

d. At what range of prices will the firm produce a positive output？

f.At what range of prices will the firm earn a positive profit.

Suppose that labor is the only variable input to the production process. If the marginal cost of production is diminishing as more units of output are produced, what can you say about the marginal product of labor？

某公司的短期总成本函数由等式TC=200+55q给出，式中，TC为总成本; q为总产出数量;两者均以千计。

(1)该公司的固定成本是多少？

(2)如果该公司生产了100000单位的产品，它的平均可变成本是多少？

(3)其所生产的单位产品的边际成本是多少？

(4)其平均固定成本是多少？

(5)假定该公司通过贷款扩大生产规模，其固定成本增加5000美元，但其可变成本降至每1000单位产品45000美元，利率i也进入成本函数。利率每上升1%，成本增加3000美元。写出新的成本函数。

The short - run cost function of a company is given by the equation TC = 200 +55q, where TC is the total cost and q is the total quaintly of output ，both measured in thousands.

a. What is the company' s fixed cost？

b. If the company produced 100000 units of goods, what is its average variable cost？

c. What would be its marginal cost of production？

d. What would be its average fixed cost？

e. Suppose the company borrow money and expands its factory. Its fixed cost rises by

$ 50000, but its variable cost falls to $ 45000 per 1000 units. The cost of interest (i) also enters into the equation. Each one-point increase in the interest rate raises costs by $ 3000. Write the new cost equation.

(1)假设某厂商的产量函数为q=9x^1/2,在短期，固定成本为1000美元，x为可变投入，其成本为4000美元/单位。生产q单位产品的总成本为多少？[即求出总成本函数C(q)]

(2)写出供给曲线方程。

(3)如果价格为1000美元，厂商产量为多少？利润水平为多少？在成本曲线图上表示出你的结论。

a. Suppose that a firm's production function is q=9x^1/2in the short nun, where there are fixed costs of $ 1000, and x is the variable input whose cost is S 4000 per unit. What is the total cost of producing a level o[ output q？ In other words, identify the total cost function C(q)？

b. Write down the equation for the supply curve.

e. If price is $ 1000, how many units will the firm produce？ What is the level of profit？ Illustrate your answer on a cost - curve graph.