作者BaBi (迅雷不及掩耳盗铃)
看板trans_math
标题Re: [张爸] 求点到线之距离
时间Wed May 29 01:36:08 2013
※ 引述《winter5690 (bbv)》之铭言：
: 各位大大安安
: 想请问一个题目
: find the distance from the point(2,1,3) to the line
: x-1/2 = y/-1= z+1/1.
: 我的作法是: 将x-1/2 = y/-1= z+1/1 写成2x-y+z-1=0
: (2,1,3)代入,答案为(5/6)^0.5
: 但是正确答案不是这个,想问我是哪边出错了?
拜托下次请把数学式写好, 到底是 (x-1)/2 还是 x-(1/2)?
P(2,1,3)
Q(1+2t,-t,t-1)
PQ = (2t-1,-t-1,t-4)
(2t-1,-t-1,t-4) dot (2,-1,1) = 6t-5 = 0, t= 5/6
PQ = (4/6,-11/6,-19/6)
distance = sqrt(498/36) = sqrt(83/6)
--
※ 发信站: 批踢踢实业坊(ptt.cc)
◆ From: 114.41.133.189
1F：→ winter5690:sorry啦~那如果是求到平面的距离呢?140.124.141.113 05/29 01:43
2F：→ suhorng:那你给的平面是什麽？ 140.112.30.135 05/29 09:30
3F：→ suhorng:一条直线周围可是有一整圈平面阿 140.112.30.135 05/29 09:30
4F：推 Yugen:我好开心XDDDD...118.163.178.157 05/30 01:50
5F：→ BaBi:? 114.41.133.189 05/30 02:45
6F：→ winter5690:开心什麽..140.124.141.113 05/30 16:56