y=sin^2x-sinxcosx+1/2的值域

问题描述:

y=sin^2x-sinxcosx+1/2的值域

y=sin^2x-sinxcosx+1/2=sin^2x-1/2+sinxcosx+1=-cos2x/2+sin2x/2+1
=(sin2x-cos2x)/2+1
值域是(-根号2/2+1,根号2/2+1)