" If "cos x+cos y-cos(x+y)=(3)/(2)

Find all the pairs of x,y that satisfy the equation cos x+cos y+cos(x+y)=-(3)/(2)

Show that (i) cos x+cos y=2 cos (x+y)/(2) cos (x-y)/(2) (ii) cos x-cos y=-2 sin (x+y)/(2) sin (x-y)/(2) (iii) sin x+sin y=2 sin (dot(x)+y)/(2) cos (x-y)/(2) (iv) sin x-sin y=2 cos (x+y)/(2) sin (x-y)/(2)

If x + y = (2pi)/(3) and cos x + cos y = (sqrt(3))/(2) l find x and y.

The minimum value of cos x+cos y+cos(x+y) is

If (cos x)/(cos y)=2 and cos(x-y)=(sqrt(3))/(2) then tan y=

If (cos x)/(cos y)=2 and cos(x-y)=(sqrt(3))/(2) then tan y=sqrt(alpha)-beta value of alpha-beta=

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)

If cos x+cos y=(3)/(2)+cos(x+y) then for n in I

if x and y are acute angles such that cos x+cos y=(3)/(2) and sin x+sin y=(3)/(4) then sin(x+y)=