—Are you getting ready__________ the exam?
—Yes, we are.
A:to
B:for
C:in
D:at
一 What is he interested in?
— Playing chess.
脱式计算。
600+345-278
(Ⅰ)求函数f(x)在0,π上的单调递增区间;
(Ⅱ)在△ABC中,a、b、c分别为角A、B、C的对边,f(A)= 14 ,a=3,求△ABC面积的最大值.
如图,AC与BD互相平分于点O,则△AOB至少绕点O旋转多少度才可与△COD重合( )