假设某种商品的需求曲线为Q=10-2P+P_s.其中，P是垓商品的价格，而Ps是某种替代品的价格。己知

(1)如果P=1.00美元，需求的价格弹性为多少？交叉价格弹性又等于多少昵？

(2)如果垓商品的价格P上涨到2.00美元，那么现在需求的价格弹性为多少？交叉价格弹性昵？

Supuose: the demand curve for a producl is given by Q=10-2P+P,, where P is the price of the produet and P, is the price of a subtitute good. The price of the substitute god is S 2.00.

(a) SupposeP= S 1. 00. What is the price elasticity of demand？ What is the cross-price elas- ticity of demand？

(b) Suppose the price of the good, P, inereases to $ 2.00. Now whal is the price clasticily of demand，and what is the cross-price elasticity of demand？