化简f(x)=2coscos(π/6-x)-√3 sin²x+sinxcosx
1个回答

你可能是忙中出错了!题目应该是这样的:

化简:f(x)=2cosxcos(π/6-x)-√3(sinx)^2+sinxcosx.

[解]

f(x)

=2cosx[cos(π/6)cosx+sin(π/6)sinx]-√3(sinx)^2+sinxcosx.

=2cosx[(√3/2)cosx+(1/2)sinx]-√3(sinx)^2+sinxcosx.

=√3(cosx)^2+sinxcosx-√3(sinx)^2+sinxcosx.

=√3[(cosx)^2-(sinx)^2]+2sinxcosx

=√3cos2x+sin2x

=2[(√3/2)sin2x+(1/2)cos2x]

=2[sin2xcos(π/6)+cos2xsin(π/6)]

=2sin(2x+π/6).