Math:Equation of straight line

2009-06-28 11:59 pm
1.Find the point of intersection between L1: x+3y- 4=0 and L2: 2x+ 6y+3=0

2. Show that the straight lines L1: 2x-y-4=0 and L2: 6y+3x-4=0 are perpendicular with different y-intercepts.

回答 (2)

2009-06-29 1:06 am
✔ 最佳答案
1.
Slpoe of L1=-(1/3)
Slpoe of L2=-(2/6)=-1/3
∴L1//L2
∴The point of intersection=0

2.

L2: 6y+3x-4=0
i.e. 3x+6y-4=0

y-intercepts of L1=-(-4/-1)=-4
y-intercepts of L2=-(-4/6)=2/3

Slpoe of L1=-(2/-1)=2
Slpoe of L2=-(3/6)=-1/2
(Slpoe of L1) (Slpoe of L2)=(2)(-1/2)
=-1
2009-06-29 12:13 am
先給你一點提示:

1. 只要solve 了equation 找出 x=?, y=? 就是 point of intersection

2. Slope of Equation = -A/B,
你計出 L1 及 L2 的 slope, 若他們 perpendicular, slope相乘便是 -1

y-intercept 的問題,代 x=0 入 L1, 計到的 y值便是 L1的 y-intercept

最後希望你計數多用腦筋


收錄日期: 2021-04-23 20:38:47
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090628000051KK01059

檢視 Wayback Machine 備份