1
sina=-√(1-cos²a)=-√(1-9/25)=-√16/25=-4/5
tga=sina/cosa=-4/5:3/=-4/5*5/3=-4/3
ctga=1/tga=1:(-4/3)=-3/4
2
(2+3i)/(4+3i)(2-i)=(2+3i)/(8-4i+6i-3i²)=(2+3i)/(8+2i+3)=(2+3i)/(11+2i)=
=(2+3i)(11-2i)/(11+2i)(11-2i)=(22-4i+33i-6i²)/(121-4i²)=(22+6+29i)/(121+4)=
=(28+29i)/125=28/125+29/125*i
5
a)y`=(2x+3)`*(x²-1)+(2x+3)*(x²-1)`=2*(x²-1)+(2x+3)*2x=2x²-2+4x²+6x=
=6x²+6x-2
b)y`=(sin²3x)`*(sin3x)`*(3x)`=2sin3x*cos3x*3=3sin6x
7
9 1/3-1 2/3=7 2/3