— Excuse me, sir. Please don't take photos in the museum. Look at the sign .
— I'm sorry. I didn't notice it just now.
A:
B:
C:
D:
Today is C____ Day. We are very happy.
圆x=2cosθy=2sinθ(θ为参数)与直线3x﹣4y﹣9=0的位置关系是( )
自从“五四”以来,翻译介绍先进国家的文化成果就成了中国人民的迫切要求。 。
函数y=sinπx+φφ>0的部分图象如右图所示,设P是图象的最高点,A,B是图象与x轴的交点,则tan∠APB=( )