Question

cos^2x-sin^2x=sqrt 2/2

Answer 1

$cos^2x-sin^2x= frac{ sqrt{2} }{2}$
$cos2x= frac{ sqrt{2} }{2}$
$2x=бarccos frac{ sqrt{2} }{2} +2 pi n,$ $n$ ∈ $Z$
$2x=бfrac{ pi }{4} +2 pi n,$ $n$ ∈ $Z$
$x=бfrac{ pi }{8} + pi n,$ $n$ ∈ $Z$