f(x)=(sinx)^2+「3sinxcosx+2(cosx)^2=(sinx)^2+(cosx)^2+(cosx)^2+「3sinxcosx=1+(1+cos2x)/2+(「3/2)*2cosxsinx=3/2+sin(2x+派/6)~~~T=2派/2=派~~~f(x)值域为[0.5,2.5]~~~~~~~~~~~~$@\$\\~~(「表根号,手机打不出根号)→→←←←相关公式：倍角公式.,(cosx)^2=(1+cos2x)/2~...(sinx)^2=(1-cos2x)/2...