若可导函数
f(x)满足[
]|
A .2f(1)>f(2) |
B .2f(2)>f(1) |
|
C .f(1)>f(2) |
D .f(1)<f(2) |
设
[
]|
A .sinx |
B .-sinx |
|
C .cosx |
D .-cosx |
椭圆
[
]|
A . |
B . |
|
C . |
D . |
若双曲线
[
]|
A . |
B . |
|
C . |
D .±2 |