Question

2sin2x+cosx+4sinx+1=0

Answer 1

2sin2x+cosx+4sinx+1=0

4sinxcosx+cosx+4sinx+1=0

4sinx(cosx+1)+cosx+1=0

(cosx+1)(4sinx+1)=0

cosx=-1                     sinx=-1/4

x=pi+2pik . k=z         x=(-1)^(n+1) *arcsin(1/4) +pik . k=z