Question

Решите уравнение, срочно

Answer 1

$8sin^2x+cosx+1=0\\ 8-8cos^2x+cosx+1=0\\-8cos^2x+cosx+9=0\\D=1+288=17^2\\cosx_{1,2}= \frac{-1б17}{-16} = |{ {{-1} \atop { \frac{18}{16} }} \right. \\cosx=-1\\x= \pi +2 \pi n,NprinZ$, 
Ответ: $x= \pi +2 \pi n$, N∈Z