已知tanα=2,则(2sin^2α+1)/(sin2α)等于多少
问题描述：
已知tanα=2,则(2sin^2α+1)/(sin2α)等于多少
答
=(2sin^2α+1)/(2sinα·cosα)
=(2tan^2 α + 1/cos^2 α)/(2tanα)
=(2tan^2 α + sec^2 α)/(2tanα)
=(3tan^2 α + 1)/(2tanα)
= 13/4