点P到圆心的距离=√（4+9）=√13,圆心坐标（0,0）设相切于点A（X1,Y1）AP^2=(X1-2)^2+(Y1-3)^2OA=半径=2AP^2+OA^2=OP^2(X1-2)^2+(Y1-3)^2+4=13又有x1^2+y1^2=4解得 X1=2 Y1=0 或 X1=10/13 Y1=32/39K=(0-3)/(2-2)(不...
