A:①③
B:①④
C:②③
D:②④
已知双曲线x2cos2θ-y2sin2θ=1(π2<θ<π)的右焦点为F,P是右支上任意一点,以P为圆心,PF长为半径的圆在右准线上截得的弦长恰好等于PF,则θ的值为( )
抛物线y=2(x-3)2+1的顶点坐标为____ .
对于闭合电路欧姆定律的理解,下列说法一定正确的是( )
A.the Great Wall B.Mount Fuji C.the Statue of Liberty
D.Big Ben E.the Merlion F.the Eiffel Tower
____from China
____from British
____from Singapore.
____from Japan.
____from USA
____from France.