[20Sx+cos y=a,cos2x+cos2y=b],[" then "]

If cos x+cos y=a and cos2x+cos2y=b then the value of cos x cos y=(lambda a^(2)+mu b-2)/(4) the value of 2 lambda-mu 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 y=cos(2cos^(-1)x)," then "y''=

If sin x+sin y=a and cos x+cos y=b, then tan((x+y)/2 ' is equal to

If sin x+sin y=a and cos x+cos y=b then cos(x-y) is equal to (1)/(2)(a^(2)+b^(2)-2)(B)(1)/(2)(a^(2)+b^(2)+2)

If 0 le x, y le 2 pi "and cos"x + "cos" y = -2, " then "cos" (x+y)=

If 0 le x, y le 2 pi "and cos"x + "cos" y = -2, " then "cos" (x+y)=

If sin x + sin y = a and cos x + cos y = b then tan ((x + y) / (2)) is