y=[2(sinx)^2+1]/sin2x
=[3(sinx)^2+(cosx)^2]/2sinxcosx
=(3/2)sinx/cosx+(1/2)cosx/sinx
>=2*[(3/2)*(1/2)]^(1/2)
=3^(1/2)
均值不等式的应用.
y=[2(sinx)^2+1]/sin2x
=[3(sinx)^2+(cosx)^2]/2sinxcosx
=(3/2)sinx/cosx+(1/2)cosx/sinx
>=2*[(3/2)*(1/2)]^(1/2)
=3^(1/2)
均值不等式的应用.