2cos^2x+sinx*cosx+1=0

[latex]2\cos^2x+\sin x\cdot\cos x+1=0, \\ 2\cos^2x+\sin x\cdot\cos x+\sin^2x+\cos^2x=0, \\ 3\cos^2x+\sin x\cdot\cos x+\sin^2x=0, \\ 3+\frac{\sin x}{\cos x}+\frac{\sin^2x}{\cos^2x}=0, \\ tg^2x+tgx+3=0, \\ tgx=a, \\ a^2+a+3=0, \\ D=-11\ \textless \ 0, \\ a\in\varnothing, \\ x\in\varnothing.[/latex]