Question

решите уравнение Sin^2x +2cosx +2 =0

Answer 1

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