已知sin(阿尔法+π/3)=a,那么根号3sin - 知识问答

已知sin(阿尔法+π/3)=a,那么根号3sin阿尔法-cos阿尔法的值

2个回答

√3sina-cosa(用辅助角公式)
=2sin(a-π/6)
=2sin(a- π/6 + π/2 -π/2)
=2sin(a+π/3 - π/2)
=-2sin[π/2 -(a+π/3)]
=-2cos(a+π/3)
=-2√(1-a平方)

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