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本帖最後由 凸唯而出 於 11-9-22 10:36 PM 編輯
31
y = mx + c
we have
2x - y +4 =0
thus that y = 2x + 4
Since B is on the y-axis, let it be (0,y)
y = 2(0) +4
y = 4
Since A is on the y-axis, let it be (x,0)
0 = 2x + 4
x = -2
A = (-2,0) , B = (0,4)
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slope of L1 is 2
slope of L1 x slope of L2 = -1 ( perpendicular)
2 x slope of L2 = -1
slope of Lx = - 1/2
let anther point on L2 be ( x , y)
y - 4 1
-------- = - ---
x - 0 2
2y -8 = - x
2y + x -8 =0
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計左 a 同 b , 之後你識的
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32
let another point on the line be (x,y)
y - 3 - 4
------ = ---
x - 10 3
3y + 4X - 49 = 0
----------------------------
3-h -4
----- = ---
10- 3 3
h = 15
------------------------------
i 同 b 一樣禁計
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ii 之後你識計的
我都唔知對/錯
請樓主小心.......
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