Suppose a capital market opens, which allows Robin to borrow or lend with the April Crusoe on the other islands. The borrowing and lending rate is r = 0.2.

(b) What is the present value of Robin’s wealth assuming he uses the optimal production plan? (5 points)

【已刪除】1. A monopolist’s total cost (TC) and total revenue (TR) functions are assumed to respectively，where Q denotes the output quantity. The government is going to impose a tax of t dollars per unit quantity on the commodity produced by the firm. The government wants to maximize T=tQ, the total revenue it realizes from the tax. However, the government does not know what tax rate t will accomplish that end. Find the tax rate t that maximizes total tax revenue 丁 for the government and the equilibrium quantity Q for which the firm’s profit is maximized after taxation. (20 points)

【已刪除】 (a) 

【已刪除】(b) ，where A，a, b, a and p are parameters. The prices of the two goods，x and y，and income are denoted by Px, Py，and I， respectively. (20 points)

(a) Determine Robin Crusoe’s optimal production/consumption pattern. (10 points) 

(1)在公開市場買入政府債券。

(2)降低所得稅稅率。

(3)信用卡發卡銀行降低（或免）年費，大量推廣信用卡的使用。

【已刪除】5 •假設有一總體經濟模型： 式中y,P,N,W,i及M分別代表所得、物價水準、就業量、名目工資率、利率 和貨幣供給量。(AO爲生產函數對N的一階導數。假設此經濟體名目工資率 完全僵固，致勞動市場成爲由需求面決定(demand-determined),則貨幣供給（M) 增加後，對內生變數y,P及i的影響爲何？（25分）

【已刪除】(c)

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