题目
题型:不详难度:来源:
答案
AB |
a |
AD |
b |
AP |
c |
∵PA⊥平面ABCD,
∴
a |
c |
b |
c |
∵∠ABC=60°,四边形ABCD为菱形,
∴
a |
b |
a |
b |
b |
=-
1 |
2 |
b |
AE |
AB |
BE |
a |
1 |
2 |
b |
PD |
PA |
AB |
BC |
CD |
c |
a |
b |
a |
b |
c |
AE |
PD |
a |
1 |
2 |
b |
b |
c |
=
a |
b |
1 |
2 |
b |
a |
c |
1 |
2 |
b |
c |
=-
1 |
2 |
b |
1 |
2 |
b |
∴
AE |
PD |
∴AE⊥PD.
核心考点
举一反三
DF |
AB |
AC |
PM |
1 |
2 |
MP′ |
(1)求点M的轨迹.
(2)若F1(-
5 |
5 |
题型:MF2|的最大值.
10 |
(1)求直线CD的方程;
(2)求圆P的方程;
(3)若直线AB与x轴交于点M,求
MC |
MD |
(1)试用
AB |
AC |
AD |
AG |
(2)若∠BAC=60°,∠CAD=∠DAB=45°,|
AB |
AC |
AD |
AG |
AB |
3 |
OA |
OB |