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發問:

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).

最佳解答:

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

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