已知sinx+cosx/sinx-cosx=3那么tan x
问题描述:
已知sinx+cosx/sinx-cosx=3那么tan x
答
∵(sinx+cosx)/(sinx-cosx)=3
==>(sinx/cosx+1)/(sinx/cosx-1)=3
==>(tanx+1)/(tanx-1)=3
==>tanx+1=3(tanx-1)
==>2tanx=4
∴tanx=2.