f(x)=2cos(2x+π/3)+√3(sinx+cosx)^2.若ABC分别为△ABC三个角,且cosB=1/3,f[(π/4)+(C/2)]=√3/2.C为锐角,求sinA.

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f(x)=2cos(2x+π/3)+√3(sinx+cosx)^2.若ABC分别为△ABC三个角,且cosB=1/3,f[(π/4)+(C/2)]=√3/2.C为锐角,求sinA.

f(x)=2cos(2x+π/3)+√3(sinx+cosx)^2.若ABC分别为△ABC三个角,且cosB=1/3,f[(π/4)+(C/2)]=√3/2.C为锐角,求sinA.
f(x)=2cos(2x+π/3)+√3(sinx+cosx)^2.若ABC分别为△ABC三个角,且cosB=1/3,f[(π/4)+(C/2)]=√3/2.
C为锐角,求sinA.

f(x)=2cos(2x+π/3)+√3(sinx+cosx)^2.若ABC分别为△ABC三个角,且cosB=1/3,f[(π/4)+(C/2)]=√3/2.C为锐角,求sinA.
f(x)=2cos(2x+π/3)+√3(sinx+cosx)^2
=cos2x-√3sin2x+√3(1+sin2x)
=cos2x+√3,
f[(π/4)+(C/2)]=cos(π/2+C)+√3=-sinC+√3=√3/2,∴sinC=√3/2,cosC=1/2.
sinB=(2√2)/3,
∴sinA=sin(B+C)=(2√2)/3*1/2+1/3*√3/2=(2√2+√3)/6.