F.5 A.Maths
2007-01-01 6:15 pm
Find the coordinates of the points which divide internally and externally in the ratio 2:1 the line joining the points (-7,7),(-1,-2).
回答 (1)
2007-01-01 6:24 pm
✔ 最佳答案
let the point P is (x,y)when the points which divide internally
x=(2*-1+-7)/(2+1)=-3
y=(2*-2+7)/(2+1)=1
Thus the point P is (-3,1)
when the point Q (x,y) which divide externally
PQ:QR=1:1
then
-1=(x-7)/2
x=5
-2=(7+y)/2
y=-3
so Q (5,-3)
then
2007-01-01 10:25:34 補充：
PQ:QR=1:1 應是PR:QR=1:1
收錄日期: 2021-04-25 16:50:41
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