1.A point A(2,3) lies on a line L with slope 5/4. Find two other points
that lie on lineL.
2. Suggest a way to trisect the line segment joining A(-3,-1) and B(6,50 in a rectangular coordinate plane.
Maths
2009-08-01 3:50 am
回答 (1)
2009-08-01 5:01 am
✔ 最佳答案
1)The equation of L :
(y-3) / (x-2) = 5/4
5x-10 = 4y-12
5x - 4y + 2 = 0......(1)
Sub x = 0 to (1) , y = 1/2 , so (0 , 1/2) lie on L ,
Sub y = 0 to (1) , x = - 2/5 , so ( - 2/5 , 0) lie on L.
You can sub other values to x or y to get other points lie on L.
2.
Let a(c,d) , b(e,f) be trisect points of AB , then :
Aa = ab = bB
For coordinate y :
d-(-1) = f - d = 50 - f
d+1 = f-d , so f = 2d+1
From d+1 = 50-f
d+1 = 50 - (2d+1)
d = 16
f = 33
For coordinate x :
c - (-3) = e - c = 6 - e
c+3 = e-c , so e = 2c+3
From c + 3 = 6 - e ,
c + 3 = 6 - (2c+3)
c = 0
e = 3
So a( 0 , 16) and b(3 , 33) are trisect point of AB.
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