Все на картинке
sqrt(32)=2sqrt(8) sqrt(8)-sqrt(32)sin^2(11Pi/8)=sqrt(8)*(1-2sin^2(11Pi/8))= =sqrt(8)*cos2*(11Pi/8)=sqrt(8)*cos(11Pi/4)= =sqrt(8)* cos((12Pi-Pi)/4)=sqrt(8)*cos(3Pi-(Pi/4))= =sqrt(8)*(-cos(Pi/4))=sqrt(8)*(-sqrt(2)/2)=-4sqrt(2)