bar(4)sin^(2)y+cos^(-(j)/(x)y')=k

Prove that (cos x +cos y)^(2)+(sin x-sin y)^(2)=4 cos^(2) ((x+y)/(2))

If (cos^(4)x)/(cos^(2)y)+(sin^(4)x)/(sin^(2)y)=1 , then (cos^(4)y)/(cos^(2)x)+(sin^(4)y)/(sin^(2)y) equal :

Prove that (cos x + cos y)^(2) + (sin x + sin y)^(2) = 4 cos^(2) ((x-y)/(2))

Find (dy)/(dx) at x=1,y=(pi)/(4) if sin^(2)y+cos xy=k

Prove that: quad (cos x+cos y)^(2)+(sin x-sin y)^(2)=4cos^(2)(x+y)/(2)

If 2^(sin x+cos y)=1 and 16^(sin^(2)x+cos^(2)y)=4 , then find the value of sin x and cos y

Prove that : (cos x - cos y)^(2) + (sin x - sin y)^(2) = 4 sin^(2) ((x - y)/(2))

Prove that (cos x-cos y)^(2)+(sin x-sin y)^(2)=4 sin ^(2)((x-y)/(2))

If (cos ^ (4) x) / (cos ^ (2) y) + (sin ^ (4) x) / (sin ^ (2) y) = 1 then prove that (cos ^ (4) y) / (cos ^ (2) x) + (sin ^ (4) y) / (sin ^ (2) x) = 1

(cos x- cos y) ^(2) + (sin x - sin y) ^(2) =4 sin ^(2) "" ( x-y)/(2)