माना `alpha ,beta ` इस प्रकार है की ` pilt alpha -beta lt3pi` यदि `sin alpha +sin beta =-21//65 `और ` cos alpha +cos beta =-27//65` तब ` cos"" ( alpha-beta )/( 2)`का मान है :

sin alpha + sin beta = 1/4 and cos alpha + cos beta = 1/3 The value of cos ( alpha + beta) is

Let alpha, beta" such that "pi lt alpha-beta lt 3pi." If sin "alpha+sin beta=-21//65 cos alpha+cos beta=-27//65 , then find the value of cos ""(alpha-beta)/(2) .

Let alpha, beta be such that pi lt alpha-betalt3pi if sin alpha+sinbeta = -21/65 and cos alpha+cos beta = -27/65 , then the value of cos(alpha-beta)/(2) is

Let alpha , beta be such pi lt alpha- beta lt 3 pi if sin alpha + sin beta = (-21)/(65) , and cos alpha Cos beta = (-27)/(65) then the value of cos ( alpha - beta)/(2) is

Let alpha,beta be such that pi lt alpha-beta lt3 pi . If sin alpha+ sin beta=(-21)/65 and cos alpha+ cos beta=(-27)/65 , then the value of cos((alpha-beta)/2) is

Let alpha , beta be such that pi lt alpha - beta lt 3 pi . If sin alpha + sin beta =-(21)/(65) and cos alpha + cos beta =-(27)/(65) , then the value of cos""(alpha - beta )/(2) is

Let alpha, beta be such that it pi < alpha - beta <3 pi . if sin alpha + sin beta =-21/65 and cos alpha+cos beta = -27 / 65 then the value of cos ((alpha-beta)/2) is

Let alpha, beta be such that it pi < alpha - beta <3 pi . if sin alpha + sin beta =-21/65 and cos alpha+cos beta = -27 / 65 then the value of cos ((alpha-beta)/2) is