问题
选择题
f(x)=2cosxsin(x+
|
答案
f(x)=2cosxsin(x+
)-π 3
sin2x+sinxcosx3
=2cosx(
sinx+1 2
cosx)-3 2
sin2x+sinxcosx3
=2sinxcosx+
cos2x-3
sin2x3
=sin2x+
cos2x=2sin(2x+3
)π 3
∴T=
=π2π 2
故选C.
f(x)=2cosxsin(x+
|
f(x)=2cosxsin(x+
)-π 3
sin2x+sinxcosx3
=2cosx(
sinx+1 2
cosx)-3 2
sin2x+sinxcosx3
=2sinxcosx+
cos2x-3
sin2x3
=sin2x+
cos2x=2sin(2x+3
)π 3
∴T=
=π2π 2
故选C.