17.
A(k,2)andB(-1,-2)are two points in a rectangular
coordinate plane.If OA=OB,where O is the origin,find
the value(s) of k.
21.The slope of L (係a點同b點既線所得出既斜率)is -1/2.
Find the coordinates of pointB(0,y),A點係(-4,1)
24.Two points A(-3,5)and B(6,-4)are given.The line segment AB
intersects the x-axis at point P.Find
a)AP:PB
b)the coordinates of P.
plz help!!!
請問一d距離公式既問題
2007-04-23 5:26 am
回答 (1)
2007-04-23 6:55 am
✔ 最佳答案
17OA=OB
OA^2=OB^2
k^2+4=1+4
k^2=1
k=1 or -1
21
The slope of L (係a點同b點既線所得出既斜率)is -1/2
So
(y-1)/(0+4)=-1/2
y-1=-2
y=-1
coordinates of pointB is(0,-1)
24
using two point form
the equation of L passing through A,B is
(y-5)/(x+3)=(-4-5)/(6+3)
(y-5)/(x+3)=-1
y-5=-x-3
x+y-2=0
代y=0,x=2
P(2,0)
AP=√[(2+3)^2+25]=√50
PB=√[(2-6)^2+16]=√32
AP:PB
=√50:√32
=√(50/32)
=√(25/16)
=5:4
(b)
the coordinates of P is (2,0)
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