Question

已知过点P(0,1)的直线与两点A(-1,5) ,B(4,-2) ,若直线l与线段AB相交,求直线l的斜率的取值范围

Answer 1

过B时, k = (-2-1)/(4-0) = -3/4

过A时, k = (5 - 1)/-1-0) = -4

画个草图可知,斜率的取值范围: k ≥ -3/4或 k ≤ -4 (并集)