a=(3,4),b(2,-1),向量a+xb與a-b垂直，求ｘ。（上述向量向右)
已知M1(1,5),M2(2,3),求線段M1,M2的兩個三等分點的坐標。
已知A(x,2),B(5,1),C(-4,2x)在同一直線上，求x
已知點P分AB所成的比是3/4，則A分BP所成的比是______？(上述向量向右)
求我呀!!!唔該點做,急問,四題
2007-06-12 5:03 am
回答 (2)
2007-06-12 5:31 am
✔ 最佳答案
1)a+xb = (2x + 3, -x + 4)
a-b = (1,5)
(2x + 3, -x + 4) * (1,5) = 0
2x + 3 + 5(-x + 4) = 0
x 自己搵到啦
2)
( ( 1 + 2(2) ) / (1+2), ( 5 + 2(3) ) / (1+2) ) = (5/3,11/3)
( ( 2 + 2(1) ) / (1+2), ( 3 + 2(5) ) / (1+2) ) = (4/3,13/3)
3)
1 / (x - 5) = (1 - 2x) / 9
x 自己搵到啦
4)
-7/3
2007-06-12 5:15 pm
)
( ( 1 + 2(2) ) / (1+2), ( 5 + 2(3) ) / (1+2) ) = (5/3,11/3)
( ( 2 + 2(1) ) / (1+2), ( 3 + 2(5) ) / (1+2) ) = (4/3,13/3)
( ( 1 + 2(2) ) / (1+2), ( 5 + 2(3) ) / (1+2) ) = (5/3,11/3)
( ( 2 + 2(1) ) / (1+2), ( 3 + 2(5) ) / (1+2) ) = (4/3,13/3)
收錄日期: 2021-05-03 16:05:20
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20070611000051KK04461