3sin^2 x - cos x +3=0

Question

3sin^2 x - cos x +3=0

Answer 1

3(1-cos^2x)+cos^2x-2=0
3-3cos^2x+cos^2x-2=0
-2cos^2x=-1
cos^2x=1/2
1)cosx=sqrt(2)/2
x=+-pi/4+2pi*n
2)cosx=-sqrt(2)/2
x=+-3pi/4+2pi*n
Ответ: x=+-pi/4+2pi*n; x=+-3pi/4+2pi*n