OA 、OC、OD、OE等都表示向量,t表示倍数

学习 时间:2026-03-30 10:27:16 阅读:6986
OA 、OC、OD、OE等都表示向量,t表示倍数已知3OA=OC,2OB=OD,OE=t (OA+OB),则实数t为何值时,C、D、E 三点在同一条直线上?因为OA=1/3OC,OB=1/2OD,所以OE=t/3 OC+t/2 OD,当且仅当t/3+t/2=1时C、D、E三点共线.故t=6/5,我不明白的就是为什么要t/3+t/2=1,

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无语的航空

坚强的小刺猬

2026-03-30 10:27:16

3OA=OC,2OB=OD,OE=t (OA+OB)OA=(1/3)OC,OB=(1/2)ODOE=t/3OC+ t/2ODif E is on CD,thenlet |CE|/|EC| = m:n=> OE = (nCE +mEC)/(m+n)NowOE=t/3OC+ t/2ODm+n = 1n+m = (t/3) + (t/2) = 1

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  • 含糊的大叔
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    2026-03-30 10:27:16

    3OA=OC,2OB=OD,OE=t (OA+OB)OA=(1/3)OC,OB=(1/2)ODOE=t/3OC+ t/2ODif E is on CD,thenlet |CE|/|EC| = m:n=> OE = (nCE +mEC)/(m+n)NowOE=t/3OC+ t/2ODm+n = 1n+m = (t/3) + (t/2) = 1

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