d = √(1+k^2)|x1-x2|
= √(1+k^2)[(x1+x2)^2 - 4x1x2]
= √(1+1/k^2)|y1-y2|
= √(1+1/k^2)[(y1+y2)^2 - 4y1y2]
❤您的问题已经被解答~(>^ω^