14.在平面直角坐标系xOyxOyxOy中,已知P1(0,2)P_{1}(0,2)P1(0,2),P2(4,4)P_{2}(4,4)P2(4,4)两点,若圆MMM以P1P2P_{1}P_{2}P1P2为直径,则圆MMM的标准方程为((( )))