平行四邊形ABCD中，A (2,-4) B (X1,Y1) C (3,-1) D (X2,Y2)，求X1+X2+Y1+Y2的算式?
回答 (2)
2016-09-16 8:50 pm
✔ 最佳答案
因為ABCD是平行四邊形, 所以 :AB向量 = DC向量
( X1 - 2 , Y1 + 4 ) = ( 3 - X2 , -1 - Y2 )
X1 - 2 = 3 - X2 且 Y1 + 4 = -1 - Y2
X1 + X2 = 5 且 Y1 + Y2 = - 5
X1 + X2 + Y1 + Y2 = 5 + (-5) = 0
Ans: 0
2016-09-16 2:53 pm
B(2.-1) D(3.-4)
2+(-1)+3+(-4)=0
2+(-1)+3+(-4)=0
收錄日期: 2021-05-02 14:12:12
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20160916065030AAjCirh