Question

经过下列两点的直线的斜率是否存在?如果存在,求其斜率.

Answer 1

k=(y1-y2)/(x1-x2)代入,得①k=(-1-2)/(1+3)=-3/4②k=(2+2)/(1-5)=-1

③k=(4+5)/(3+2)=9/5

④k=(0-根号3)/(3-3),不存在