If `sin x+ sin y+ sin z=3, ` then the value of `(cos x+ cos y+ cos z)` is-

If sin x+sin y+sin z=3. Find the value of cos x+cos y+cos z

If cos (x-y)+1=0, then the value of (cos x+ cos y) and (sin x+sin y) is-

If sin x + sin y + sin z = 0 and cos x + cos y + cos z = 0 then prove that cot (x+y)/2 = cot z and cos (x-y)/2 = pm 1/2

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

If cos (x-y) =-1, then the values of (cos x+ cos y) and (sin x + sin y) are respectively-

If cos x+2cos y+3cos z=sin x+2sin y+3sin z=0 then the value of sin3x+8sin3y+27sin3z is :

If 2 sin x + 5 cos y + 7 sin z = 14 then 7 tan. (x)/(2) + 4 cos y - 6 cos z =

If cos x + cos y =2, then value of sin x + sin y is

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