题目内容
A．2sin(2x+)
B．2sin(2x-)
C．2cos(2x+)
D．2cos(2x-)
化简为
[ ]
A.sin2x B.sin2x C.2sin2x D.3sin2x
化简sin(x＋y)sin(x－y)－cos(x＋y)cos(x－y)的结果是
A．sin2x
B．cos2x
C．－cos2x
D．－sin2x
sin2x-cos2x等于 ( )
)
)
)
)
sin2x-cos2x等于 ( )
sin2x-cos2x等于 ( )
))))
sin2x B.sin2x C.2sin2x D.3sin2x