[sin x+sin y=a,cos x+cos y=b," then "],[" the value of "sin(x+y)" is "]

If cos x + cos y = 2, "then the value of" sin(x + y) is-

If sin x+sin y=a and cos x+cos y=b then thevalue of sin(x+y) is

If sin x + sin y = a , cos x - cos y = b then the value of tan ((y-x)/2) is _______ in terms of a and b.

If sin x + sin y = a, cos x + cos y = b, then what is the value of cos (x-y) ?

Suppose that 'a' is a non-zero real number for which sin x+sin y=a and cos x + cos y= 2a . The value of cos(x-y) is

Suppose that 'a' is a non-zero real number for which sin x+sin y=a and cos x + cos y= 2a . The value of cos(x-y) is

If sin x+sin y=3(cos y-cos x) then the value of sin 3 x+sin 3 y=

If (sinx + sin y ) = a and (cos x + cos y ) = b what is the value of sin x sin y + cos x cos y ?

If sin (x+y)=cos (x-y), then the value of cos^2x is :