如图，直线CD与直线AB相交于C，根据下列语句画图

阅读下面文段后按要求答题。
                                                                                                                                 读(节选)  
                                                                                               人之一生．读之一生    读海，胸怀将变得辽阔
                                                                                               从春读到夏，从小读到大  读月，方知阴晴圆缺
                                                                                               读雨，方知万物可以滋润，心灵能够洗涤    

                                                                                               读日，便不再惋惜日近黄昏
                                                                                               读雪，能领悟到嚣的纯洁，感受到冬的春意             用心品读，细细感悟
                                                                                                读风，就能触摸d4)11的脉搏，聆听天地的呼吸      阴雨中能读出晴空
                                                                                               读霞，才能于苍茫中发现辉煌，展示自己韵不屈     枯黄中能读出翠绿
                                                                                               读花，你学会倾听     沙漠中能读出清泉
                                                                                               读树，你学套成长       黑暗中能读出晨曦
                                                                                               读山，你学会攀登                                     

                                                                                                                                                                                                                                          (诗歌有删改)

      进入中学，语文课就为你开启了一扇文学之门。生活化的语文学习，个性化的阅读写作成为提升语文素养的有效途径。请你也参与进来吧，相信你一定会收获满满。

如图，Rt△ABC的内切圆⊙O与AB、BC、CA分别相切于点D、E、F，且∠ACB=90°，AB=5，BC=3，点P是边AC上的一动点，PH⊥AB，垂足为H．

（1）求⊙O的半径的长及线段AD的长；

（2）设PH=x，PC=y，求y关于x的函数关系式．