运用DD-AA模型检验外国价格水平P*短期内上升的影响。假定未来预期汇率Ee会立即与P*成比例地上升（按购买力平

运用DD-AA模型检验外国价格水平P^*短期内上升的影响。假定未来预期汇率E^e会立即与P^*成比例地上升(按购买力平价理论)，证明汇率也将立即对应P^*的上升比例而上升。如果开始时经济处于内部平衡和外部平衡点，这一平衡点会因为P^*的上升而发生改变吗？

Use the DD-AA model to examine the effects of a one-time rise in the foreign price level，P^*．If the expected future exchange rate E^erises immediately in proportion to P^*(in line with PPP)，show that the exchange rate will also appreciate immediately in proportion to the rise in P^*．If the economy is initially in internal and external balance，will its position be disturbed by such a rise in P^*？