如图,在平面直角坐标系中,以点p（1,-1）为圆心,2为半径作圆,交x轴于A、B两点,开口向下的抛物线经过

(1)
圆:(x - 1)² + (y + 1)² = 4
令y = 0,(x - 1)² = 3,x = 1 ±√3
A(1- √3,0),B(1 + √3,0)
从P向x轴作垂线,垂足E(1,0)
AE = 1 - (1- √3) = √3
PE = 1
tan∠APE = √3,∠APE = 60˚
∠APB = 2∠APE = 120˚
劣弧为1/3圆周,长为2πr/3 = 4π/3
(2)
抛物线过点A、B,对称轴x = (1- √3 + 1 + √3)/2 = 1
抛物线y = a(x - 1)² + d
抛物线顶点C(1,d)在⊙C上,令x = 1,(1 - 1)² + (y + 1)² = 4,y = -3 (舍去y = 1 > 0)
C(1,-3),d = -3
抛物线过点A:0 = a(1- √3 - 1)² - 3
a = 1
y = (x - 1)² - 3 = x² - 2x -2
(3) 在抛物线上是否存在一点D,使线段OC与PC互相平分?若存在求出D的坐标?
题有问题,描述不清.
(2)