已知一直線族的方程：
F:3x+4y+k(6x-5y+13)=0
若L為F中的一條直線,且從點A(2,1)到L的垂直距離為2單位,試求L的方程。
F4 A-MATHS.(3)
2007-05-24 6:57 am
回答 (1)
2007-05-24 7:07 am
✔ 最佳答案
(6k + 3)x + (4 - 5k)y + 13k = 0 --------------- (1)! (6k + 3)(2) + (4 - 5k)(1) + 13k ! / sqrt[ (6k + 3)^2 + (4 - 5k)^2 ] = 2
simply,
! 20k + 10 ! / sqrt (61k^2 - 4k + 25) = 2
take square and simply, you can find
k = 0 or k = -8/3
put each value of k to (1), you can find the answer
收錄日期: 2021-04-23 21:08:15
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070523000051KK04720