已知 3sin(π+α)+cos(-α)/4sin(-α)-cos(9π+α)=2,则tan α=
问题描述：
已知 3sin(π+α)+cos(-α)/4sin(-α)-cos(9π+α)=2,则tan α=
2- tan α=α,则sin（-5π-α）cos（3π+α）=
答
1,3sin(π+α)+cos(-α)/4sin(-α)-cos(9π+α)=2,【-3sinα+cosα】/【-4sinα+cosα】=2,-3sinα+cosα=-8sinα+2cosα5sinα=cosαtan α=sinα/cosα=1/52,tan α=αsin（-5π-α）cos（3π+α）=sin（π-α）co...