Сosπ/4/(1+2sin²π/4)=√2/2:(1+2*1/2)=√2/2:2=√2/2*1/2=√2/4
2sin^2x+5sin x +1
sin x=t
2t^2+5t+1=0
Д=25-8=17
t1=(-5+√17)/4
t2=(-5-√17)/4
sin x=t
sin x=(-5+√17)/4
32 - 4X = X^2
X^2 + 4X - 32 = 0
D = 16 + 128 = 144 ; V D = 12
X1 = ( - 4 + 12 ) : 2 = 4
X2 = ( - 16 ) : 2 = ( - 8 )