sin(2x+1/3π)=sin2xcos1/3π+sin1/3πcos2x
=1/2sin2x+二分之更号三倍的cos2x
则 2sin(2x+1/3π)=sin2x+更号三倍的cos2x
则 f(x)=2sin2x-sin2x-更号三倍的cos2x
=sin2x-更号三倍的cos2x
=1/2(1/2sin2x-二分之更号三cos2x)
=1/2(cos1/3πsin2x - sin1/3πcos2x)
=1/2sin(2x-1/3π)
到这一步应该就是你想要的答案了
sin(2x+1/3π)=sin2xcos1/3π+sin1/3πcos2x
=1/2sin2x+二分之更号三倍的cos2x
则 2sin(2x+1/3π)=sin2x+更号三倍的cos2x
则 f(x)=2sin2x-sin2x-更号三倍的cos2x
=sin2x-更号三倍的cos2x
=1/2(1/2sin2x-二分之更号三cos2x)
=1/2(cos1/3πsin2x - sin1/3πcos2x)
=1/2sin(2x-1/3π)
到这一步应该就是你想要的答案了