1.公式一d = √(1+k²)|x1-x2| = √(1+k²)[(x1+x2)² - 4x1x2] = √(1+1/k²)|y1-y2| = √(1+1/k²)[(y1+y2)² - 4y1y2]关于直线与圆锥曲线相交求弦长,通用方法是将直线y=kx+b代入曲线方程...