3 cos^2 x+2 sin x * cos x=0 СРОЧНО!!!

Question

3 cos^2 x+2 sin x * cos x=0
СРОЧНО!!!

Answer 1

3cosx^2+2sinxcosx=0
cosx(3cosx+2sinx)=0
cosx=0
x=pi/2+pi*n n∈Z
3cosx+2sinx=0
3cosx/sinx+2=0
3ctgx=-2
ctgx=-2/3
x=-arcctg(2/3)+pi*k k∈Z