求证:sina(1+cos2a)=sin2a*cosa.
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![求证:sina(1+cos2a)=sin2a*cosa.](/uploads/image/z/2758786-34-6.jpg?t=%E6%B1%82%E8%AF%81%EF%BC%9Asina%281%2Bcos2a%29%3Dsin2a%2Acosa.)
求证:sina(1+cos2a)=sin2a*cosa.
求证:sina(1+cos2a)=sin2a*cosa.
求证:sina(1+cos2a)=sin2a*cosa.
sina(1+cos2a)
=sina(1+2cos^2a-1)
=(2sina*cosa)*cosa
=sin2a*cosa
sina(1+cos2a)
=sina(1+2cos^2 a - 1)
=sina×2cos^2a
=2sinacosa × cosa
=sin2a ×cosa
sina(1+cos2a)=sina*2*(cosa)^2.
=sin2a*cosa