直线和圆锥曲线相交是解析几何中的一个重要内容.许多看上去好像与之无关的问题.如果我们通过构造直线,转化为直线和圆锥曲线相交问题来解决,则往往使得解决问题的思路变得清晰,解法变得简洁.例1定长为3的线段AB的两个端点在抛物线y2=x上移动,设线段AB的中点为M,求M到y轴的最短距离. The intersection of a straight line and a conic curve is an important part of analytical geometry. Many problems that seem to be irrelevant. If we solve the problem of the intersection of straight lines and conic curves by constructing straight lines, the solution to the problem will often become Clearly, the solution becomes simple. Example 1 The two endpoints of the segment AB with a fixed length of 3 move on the parabola y2=x. Set the midpoint of the segment AB to M, and find the shortest distance from the M to the y axis.