![]()
[ ]
|
A .-1 |
B .1 |
|
C . |
D . |
已知
tanx+tany=25,cotx+coty=30,则cot(x+y)=[ ]
|
A . |
B . |
|
C . |
D . |
![]()
[ ]
|
A .不存在 |
B .4 |
|
C .2 |
D .-4 |
![]()
[ ]
|
A .-1 |
B .1 |
|
C . |
D . |
已知
tanx+tany=25,cotx+coty=30,则cot(x+y)=[ ]
|
A . |
B . |
|
C . |
D . |
![]()
[ ]
|
A .不存在 |
B .4 |
|
C .2 |
D .-4 |