题目

On Saturday morning, John got up early to go to a sports club. On his way, he saw three of his schoolmates at the mall, Rie, Asuka and Yuki. They were always together because they were very good friends.“I'm shopping for new shoes,” Rie told John. “But I have big feet so nothing fits! We have been shopping everywhere but I can't find any big shoes!”“And we walk very slowly,” Yuki said, “because of Asuka ...”“I know,” John said, looking at Asuka. “I heard you hurt your knee in P.E. class yesterday. Does it hurt?”“It's OK if I move very slowly,” Asuka told him. “We 8．写出下列各函数关系，并判断它们是什么类型的函数．（1）写出圆的面积y（cm2）与它的周长x（cm）之间的函数关系．（2）菱形的两条对角线的和为26cm，求菱形的面积S（cm2）与一对角线长x（cm）之间的函数关系．