`((sin^2a sin^2b +sin^2a cos^2b + cos^2a)+(sin^2(2pi+a)+cos^2(6pi-a)+1))/(sin^2(pi/3-4pi)+cos^2(8pi+pi/3)+2))`

((sin ^ (2) a sin ^ (2) b + sin ^ (2) a cos ^ (2) b + cos ^ (2) a) + (sin ^ (2) (2 pi + a) + cos ^ (2) (6 pi-a) +1)) / (sin ^ (2) ((pi) / (3) -4 pi) + cos ^ (2) (8 pi + (pi) / (3)) +2))

Prove that sin^2(pi/6)+cos^2(pi/3)-tan^2(pi/4)=-1/2

Prove that: sin^2(pi/6)+cos^2(pi/3)-t a n^2pi/4=-1/2

Prove that: sin^2(pi/6)+cos^2(pi/3)-t a n^2pi/4=-1/2

sin^(2)pi/6+cos^(2)pi/3-tan^(2)pi/4=-1/2

sin^(2) (pi/6)+cos^(2) (pi/3)-tan^(2) (pi/4)=-1/2

sin ^(2)(pi/6) + cos ^(2)(pi/3) - tan ^(2)(pi/4) =- 1/2

sin pi/3 = 2sin pi/6 cos pi/6

Prove that cos^2(pi/4-B)-sin^2(pi/4-A)=sin(A+B)cos(A-B)

sin (pi/2) = 2 sin(pi/4) cos (pi/4)