y=√3sinx/2+1-2sin²x/2
设sin(x/2)=t,
∵x∈(0,π)∴x/2∈(0,π/2)
∴t∈(0,1)
y=-2t^2+√3t+1
=-2(t^2-√3/2*t+3/16)+11/8
=-2(t-√3/4)^2+11/8
t=√3/4,即sin(x/2)=√3/4时ymax=11/8
y>1(t=0,y=1)
函数y=√3sinx2+cosx,x属于(0,派)
的值域为(1,11/8]
t=tanx/2∈(0,+∞)
y=√3sinx/(2+cosx)
=√3[2t/(1+t^2)]/[2+(1-t^2)/(1+t^2)]
=√3[2t]/[2+2t^2+1-t^2]
=2√3t/(3+t^2)
=2√3/(3/t+t)
∵t+3/t≥2√3(均值定理,t=√3时取等号)
(两边取倒数,还是正值,2√3的倒数最大)
∴0