Question

РЕШИТЕ УРАВНЕНИЯ
1)3 sin^2 x+2 sin x cos x-5 cos^2 x=0
2)4 sin^3 x+4 sin^2 x-3 sin x-3=0

Answer 1

3sin^2 x+2sinxcosx-5cos^2 x=0/cos^2 x
3tg^2 x+2tg x-5=0
3t^2+2t-5=0
D=4+12*5=64
t1=1
t2=-8/6=-1 1/3
tg x=1
x=pi/4+pin
tg x=-1 1/3
x=-arctg 1 1/3+pin