3)ОДЗ
x²-3x-3≥-1⇒x²-3x-2≥0
D=9+8=17
x1=(3-√17)/2 U x2=(3+√17)/2
x≤(3-√17)/2 U x≥(3+√17)/2
x²-3x-3≤1⇒x²-3x-4≤0
x1+x2=3 U x1*x2=-4⇒x1=-1 u x2=4
-1≤x≤4
x∈[-1;(3-√17)/2] U [(3+√17)/2;4]
arctg(x²-3x-3)=π/4
arctg(x²-3x-3)=arctg1
x²-3x-3=1⇒x²-3x-4≤0
x1+x2=3 U x1*x2=-4⇒x1=-1 u x2=4
4)(sinπ/5*cosπ/5*cos2π/5)/sinπ/5=(sin2π/5*cos2π/5)/2sinπ/5=(sin4π/5)/4sinπ/5=
=sin(π-π/5)/4sinπ/5=(sinπ/5)/4sinπ/5=1/4