Question

Решите уравнение
cos^2x + cosx =0

Answer 1

$Cos^{2}x+Cosx=0\\\\Cosx(Cosx+1)=0\\\\\left[\begin{array}{ccc}Cosx=0\\Cosx+1=0\end{array}\right\\\\\\\ \left[\begin{array}{ccc}Cosx=0\\Cosx=-1\end{array}\right\\\\\\\left[\begin{array}{ccc}x=\dfrac{\pi }{2}+\pi n,n\in Z \\x=\pi+2\pi n,n\in Z \end{array}\right$