1) sin^2(3x)=cos^2(3x) 2) tg^3(x)+2tg^2(x)+3tgx=0

1) cos^2(3x) = sin^2(3x)
cos^2(3x) - sin^2(3x) = cos(6x) = 0
6x = π/2 + πk
x = π/12 + πk/6
2) tg^3(x) + 2tg^2(x) + 3tg(x) = 0
tg(x) * (tg^2 + 2tg(x) + 3) = 0

tg(x) = 0
x = πk

tg^2 + 2tg(x) + 3 = 0
(tg(x) + 1)^2 + 2 = 0
(tg(x) + 1)^2 = -2 —>Ø