如图,△ABC中,∠ACB=90°,CD⊥AB于点D,若BD:AD=1:4,则tan∠BCD的值是( )
A:14
B:13
C:12
D:2
—How do you go to school, Mr. Li?
—I _____________ to school, because it is good for my health.
What ____ Chen Jie doing?
下列函数中,是奇函数且在(0,+∞)上单调递增的为( )