Question

已知3sinθ+4cosθ=-5,求tanθ

Answer 1

3sinx+4cosx=-5,得 5sin(x+y)=-5,cosy=3/5,siny=4/5,由sin(x+y)=-1得x+y=-pai/2+2kpai,sinx=sin(-y-pai/2+2kpai)=-cosy,cosx=-siny,tanx=3/4