Solution: (x? 0，y=kx？ 0)lim[XY/(9X？ +Y？ )]=(x？ 0，y=kx？ 0)lim[kx？ /(9x？ +k？ x？ )]=k/(9+k？ )

So the limit is related to the path that the moving point (x, y) approaches (0,0) (that is, the value of k), so the limit does not exist, that is, there is no limit.