1题目展示已知点C,D是曲线x~f2/4+y~2=1的两动点,且点M(0,2),若MD=λMC,求λ的取值范围。本题是求λ的取值范围。虽然MD,MC是同向的共线向量,但利用实数与向量的积的概念仅可判定λ>0。若能发现直线MCD是过定点M(0,2)的直线束,则由运动发展观点便有了解法1。λ的变化是由 1 shows the known point C, D is the moving point of the curve x ~ f2 / 4 + y ~ 2 = 1, and the point M (0,2), if MD = λMC, find the range of λ. The problem is to find the range of λ. Although MD and MC are co-linear vectors of the same direction, the concept of the product of real numbers and vectors can only be used to determine λ> 0. If we can find the straight line MCD is a fixed point M (0,2) of the straight line, then from the point of view of the development of sports there is understanding 1. The change of λ is caused by