更新1:
Remark : 1 unit is 1 cm.
Locus
2013-11-29 2:47 am
Find the equation(s) of the locus of a point P such that it is always 6 cm. from line 2x + y - 10 = 0.
回答 (4)
2013-11-30 11:22 pm
✔ 最佳答案
Distance from point to line(2x+y-10)/root(5)=6 or -6
2x+y-10 = 6root(5) or 2x+y-10 = -6root(5)
y=-2x + 10 + 6root(5) or y=-2x + 10 - 6root(5)
2013-11-30 9:10 pm
2x+y-10=0
rearrange can become
y=-2x+10
so this equation goes through the point (0, 10)
Let P(x,y) be the locus point and it is always equal distance from the point (0,10)
so， draw a line linking these two points, using pythagoras you will get equation:
(x-0)^2 + (y-10)^2 = 6^2
rearrage gives two equations:
y = sqrt(36 - x^2) + 10
or
y = -sqrt(36-x^2) + 10
JEI YUEN LONG MATH & ENGLISH
JEI 元朗
rearrange can become
y=-2x+10
so this equation goes through the point (0, 10)
Let P(x,y) be the locus point and it is always equal distance from the point (0,10)
so， draw a line linking these two points, using pythagoras you will get equation:
(x-0)^2 + (y-10)^2 = 6^2
rearrage gives two equations:
y = sqrt(36 - x^2) + 10
or
y = -sqrt(36-x^2) + 10
JEI YUEN LONG MATH & ENGLISH
JEI 元朗
2013-11-29 5:33 am
Kwok Sir 問得好！
2013-11-29 5:24 am
你的一單位 X 和 一單位 Y 是多小 cm 呢？
收錄日期: 2021-04-27 20:36:15
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20131128000051KK00153