Cosπ/8 Сosx - Sinx Sinπ/8 >√<span>3/2
Сos(</span>π/8 + x) > √3/2
-π/6 + 2πk < π/8 +x < π/6 + 2πk , k∈Z
-π/6 + 2πk - π/8 < x < π/6 + 2πk - π/8, k∈Z
-7π/24 + 2πk < x < π/24 + 2πk , k ∈Z
Z1/z2=(3+i)/(1-2i)=(3+i)(1+2i)/[(1-2i)(1+2i)]=
=(3+6i+i-2)/(1+4)=(1+7i)/5=0,2+1,2i