求到直线距离最短时曲线上的点的坐标,通常可用两种方法即动点法与切点法.所谓动点法就是将曲线上的任意点设为P(x,f(x))或设为参数坐标,而后利用点到直线间的距离公式,讨论点P到直线距离的最值问题;切点法就是把已知直线平移,使得直线与曲线相切此时切点到直线的距离达到最小(或最大). Find the coordinates of the point on the curve when the straight line distance is the shortest, two methods are commonly used, namely the moving point method and the tangent point method, where P (x, f (x)) or As parameter coordinates, and then use the point-to-line distance formula to discuss the most value of the point P to the straight line distance problem; tangent point method is to translate the known straight line, making the straight line tangent to the curve at this point tangent to the distance Reach the minimum (or maximum).