Решите пожалуйста
4sin^2x-cosx+4=0

4sin(x)²-cos(x)+4=0

4(1-cos(x)²)-cos(x)+4=0

4-4cos(x)²-cos(x)+4=0

8-4cos(x)²-cos(x)=0

8-4t²-t=0

cos (x)=-1-√129/8

cos (x)= -1+√129/8