sqrt(32)cos^2(7Pi/8)-2sqrt(2) = ..
sqrt(32)=sqrt(16*2)=4sqrt(2) Формула: [b]2cos^2 α -1= cos2 α [/b] 4sqrt(2)cos^2(7π/8)-2sqrt(2)= 2sqrt(2)*(2cos^2(7π/8)-1)= =sqrt(2)(cos14π/8)=sqrt(2)*(cos(7π/4))=sqrt(2)*(cos(2π - (π/4))= =sqrt(2)*cos(π/4)=sqrt(2)*(sqrt(2)/2)=1