若以F1(﹣3,0),F2(3,0)为焦点的双曲线过点(2,1),则该双曲线的标准方程为____
— What's this?
— a quilt.
设f(x)是定义在R上的奇函数,且当x>0时,f(x)=lg(x2-x),则f(-2)=( )
如图,∠ACD=∠A,∠BCF=∠B,则∠A+∠B+∠ACB等于____