已知tanx 2 则sin^2x-sinxcosx

问题描述:

已知tanx 2 则sin^2x-sinxcosx

sin^2x-sinxcosx
=(sin^2x-sinxcosx)/(sin^2x+cos^2x) (上下同除以cos^2x)
=(tan^2x-tanx)/(tan^2x+1)
=2/5