设点B的坐标为(x,y),根据AB=OA和AB垂直于OA,有:
(x-5)^2+(y-2)^2=5^2+2^2=29
[(y-2)/(x-5)]*2/5=-1
解得:
x=7,y=-3或x=3,y=7
所以B点坐标为:
(7,-3)或(3,7)