解:作P1B⊥y轴,P1A⊥x轴,∵△P1OA1,△P2A1A2是等腰直角三角形,∴AP1=BP1,A1D=DA2=DP2,则OA?OB=4,∴OA=OB=AA1=2,OA1=4,设A1D=x,则有(4+x)x=4,解得x=-2+2 2 ,或x=-2-2 2 (舍去),则OA2=4+2x=4-4+4 2 =4 2 ,A2坐标为(4 2 ,0).故答案为:(4 2 ,0).