题目
题型:不详难度:来源:
(1)若四边形OABC是平行四边形,求∠AOC的大小;
(3)在(1)的条件下,设AB中点为D,OD与AC交于E,求
OE |
答案
OA |
CB |
∵四边形OABC是平行四边形,∴
OA |
CB |
|
|
OA |
OC |
OA |
OC |
又
OA |
OC |
OA |
OC |
5 |
00 |
2 |
∴co着∠AOC=
| ||
2 |
∵0°<∠AOC<080°,∴∠AOC=45°.
(2)∵为AB中点,∴D的坐标为(5,5),
又由
OE |
OD |
∴
CE |
CA |
∵A,E,C二点共线,∴
CE |
CA |
得-4×(5λ-2)=(5λ-e)×2,解得λ=
2 |
3 |
OE |
00 |
3 |
00 |
3 |
核心考点
试题【设O为坐标原点,A(8,a),B(b,8),C(a,b),(1)若四边形OABC是平行四边形,求∠AOC的大小;(3)在(1)的条件下,设AB中点为D,OD与A】;主要考察你对平面向量应用举例等知识点的理解。[详细]
举一反三
. |
OA |
. |
OC |
. |
OB |
A.2:1 | B.1:2 | C.1:1 | D.2:5 |
2 |
3 |
(1)求
AB |
AC |
(2)若
BP |
BA |
BC |
| ||
4 |
a |
3 |
b |
1 |
2 |
| ||
2 |
(1)求证:
a |
b |
(2)是否存在最小的常数k,对于任意的正数s,t,使
x |
a |
b |
y |
a |
1 |
t |
1 |
s |
b |
(Ⅰ)若点M在边BC上,且
BM |
MC |
AM |
1 |
1+t |
AB |
t |
1+t |
AC |
(Ⅱ)若点P是△ABC内一点,连接BP、CP并延长交AC、AB于D、E两点,使得AD:AC=AE:EB=1:2,若满足
AP |
AB |
AC |
MN |
题型:
|+
•
=0,则动点P(x,y)到两点M(-3,0),B(-2,3)的距离之和的最小值为______.
MP |
MN |
NP |