在解析几何中,中点、线段长(即两点间距离)等几何量,都由两点同名坐标的和、差、积、商表示,若解出有关的点的坐标再代人公式,则计算量很大,而实际上也无必要.因为由韦达定理可直接求出两点同名坐标的和与积,从而上述几何量都能求出,可省却不少繁杂的计算,在解题中应充分注意运 In analytical geometry, the geometric quantities such as the midpoint and line segment length (that is, the distance between two points) are represented by the sum, difference, product, and quotient of two coordinates with the same name. If the coordinates of the relevant point are reconstructed, The calculation is very large, but it is actually unnecessary. Because the Weida theorem can directly find the sum and product of two coordinates with the same name, so that the above geometric quantities can be found, can save a lot of complex calculations, in the solution Questions should be fully paid attention to