关于高中文科数学的函数题已知函数f（x）=2sinx•cosx﹣根号3cos2x.（1）求函数最小正周期；（2）若锐角f（@－12分之派）＝3分之2,求[email protected]的值.求 实在没有悬赏分了.
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f(x)=2sinxcosx-√3cos2x
=sin2x-√3cos2x
=2(sin2x*cosπ/3-cos2xsinπ/3)
=2sin(2x-π/3)
(1)最小正周期T=2π/2=π
(2)f(@-π/12)=2sin[2(@-π/12)-π/3]
=2sin([email protected]π/6-π/3)
=2sin([email protected]π/2)
=-2sin(π/[email protected])
=-2cos2
@=-2(2cos^[email protected])
=2/32cos^[email protected]=-1/3
cos^[email protected]=1/3
[email protected]=√3/3 (∵@为锐角 所以[email protected]>0 [email protected]>0)[email protected]=√(1-cos^[email protected])=√6/3
[email protected][email protected]/[email protected]=√6/3 / √3/3 =√2
======以下答案可供参考======
供参考答案1:
我不会求。供参考答案2:
f(x)=sin2x-根号3cox2x=2（sin（2x-1/3π）） T=2π/ω=2π/2=π