Question

2sin^²-9sin x+4=0 решите плиз

Answer 1

sin²(4x)-cos²(4x)=0
sin²(4x)-(1-sin²4x)=0
2sin²4x-1=0
sin²4x=1/2
sin4x=1/2   sin4x=-1/2
4x=π/4+π*n
x=π/16+π*n/4