Excuse me, I am doing a survey. May I know to pay?
About five times a week.( )
A.when you choose WeChat
B.whether did you try We Chat
C.how often you use WeChat
D.why do you prefer We Chat
函数f(x)=2sinxcosx是()
在平行四边形ABCD中,++=()
求值:cos2﹣sin2=()
若=(2,﹣1),=(﹣6,3),则2+=()
已知α是第四象限角,且tanα=﹣,则sinα=()