cos2A+cos(4π/3-2A)化简,
问题描述:
cos2A+cos(4π/3-2A)化简,
答
=cos2A-cos(π/3-2A)=cos2A-1/2cos2A-2分之根号3sin2A=1/2cos2A-2分之根号3sin2A=cos(2A+π/3)
cos2A+cos(4π/3-2A)化简,
=cos2A-cos(π/3-2A)=cos2A-1/2cos2A-2分之根号3sin2A=1/2cos2A-2分之根号3sin2A=cos(2A+π/3)