(sin2x-sin2y)/(cos2y-cos2x)=cot(x+y)

(sin 2x - sin 2y)/(cos 2y-cos 2x) = cot (x+y)

Prove the following Identities (sin(x+y)-2sinx+sin(x-y))/(cos(x+y)-2cosx+cos(x-y))=tanx

Let x and y be real numbers such that (sin x)/(sin y)=3 and (cos x)/(cos y)=(1)/(2). The value of (sin2x)/(sin2y)+(cos2x)/(cos2y) is (i)(49)/(58)(ii)(41)/(58)(iii)(51)/(58)( iv) none of these

(cos x + cosy)/(cos y -cos x) = cot ((x+y)/(2)) cot ((x-y)/(2))

If cot theta = cos (x+y) "and" cot phi = cos (x-y), "show that" tan (theta- phi)=(2sin x sin y )/(cos^(2) x + cos^(2) y)

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

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

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

Prove that (i) 2 cos x cos y=cos (x+y)+cos (x-y) (ii) -2 . sin x sin y=cos (x+y)-cos (x-y) (iii) 2 sin x cos y=sin (x+y)+sin (x-y) (iv) 2 cos x sin y=sin (x+y)-sin (x-y)

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