Помогите пожалуйста решить
F`(x)=[sin²(π/4-x/4)]*sin`(π/4-x/4)*(π/4-x/4)`=2sin(π/4-x/4)*cos(π/4-x/4)*(-1/4)= =-1/4*sin(π/2-x/2)=-1/4*cos(x/2) -8*(-1/4*cos(x/2))≥√2 2cos(x/2)≥√2 cos(x/2)≥√2/2 -π/4+2πk≤x/2≤π/4+2πk,k∈z -π/2+4πk≤x≤π/2+4πk,k∈z