x=π/12,2(tanx+1/tan),怎么算,
问题描述：
x=π/12,2(tanx+1/tan),怎么算,
答
2(tanx+1/tanx)
=2(sinx/cosx+cosx/sinx)
=2(1/(cosxsinx)
=4/sin2x
=4/sinπ/6
=4/sin30
=4*2=8