Question

решите уравнение Sin^2x +2cosx +2 =0

Answer 1

$1+2-cos ^2left(xright)+2cos left(xright)=0\\3-cos ^2left(xright)+2cos left(xright)=0\\cos left(xright)=-1,:cos left(xright)=3\\cos left(xright)=-1 \\x=pi +2pi k$