1A=π/32B+C=2π/3,故：C-3B=2π/3-4By=2sinB^2+cos((C-3B)/2)=1-cos(2B)+cos(π/3-2B)=1-cos(2B)+cos(2B)/2+√3sin(2B)/2=1-cos(2B)/2+√3sin(2B)/2=sin(2B-π/6)+1B∈(0,2π/3),即：2B-π/6∈(-π/6,7π/6)故：sin...