Question

1) sinx · cosx · cos2x = √3/8
2) cos²x - sin²x - sinx = 0

Answer 1

sinx *cosx *cos2x = √3/8
1/2sin2x*cos2x=√3/8
1/2sin4x=√3/4
sin4x=√3/2
4x=(-1)^n*π/3+πn, n∈z
x=(-1)^n*π/12+π/4*n, n∈z
Ответ. x=(-1)^n*π/12+π/4n, n∈z

cos²x - sin²x - sinx = 0
cos2x-sinx=0
1-2sin²x-sinx=0
2sin²x+sinx-1=0
sinx=-1 или sinx=1/2
x=-π/2+2πn, n∈z или x=(-1)^n*π/6+πk, k∈z
Ответ. x=-π/2+2πn, n∈z
            x=(-1)^n*π/6+πk, k∈z