设圆过点P(0,2), 且在轴上截得的弦RG的长为4.
(１)求圆心的轨迹E的方程；                                                                                                        
(２)过点(０，１)，作轨迹的两条互相垂直的弦、，设、 的中点分别为、，试判断直线是否过定点？并说明理由．