If `cos alpha+ cos beta =1/3` and `sin alpha+sin beta=1/4` prove that `cos[(alpha-beta)/2] =+-(5/24)`

If coa alpha+cos beta=(1)/(3) and sin alpha+sin beta prove that cos((alpha-beta)/(2))=+-(5)/(24)

If cos alpha+cos beta=1/3 and sin alpha+sin beta=1/4 ,show that tan((alpha+beta)/2)=3/4

If sin alpha + sin beta = a and cos alpha + cos beta = b, prove that : cos (alpha-beta) = 1/2 (a^2 + b^2 -2)

If cos alpha+cos beta=0=sin alpha+sin beta. Prove that cos2 alpha+cos2 beta=-2cos(alpha+beta)

If sin alpha+sin beta=a and cos alpha+cos beta=b prove that :cos(alpha-beta)=(1)/(2)(a^(2)+b^(2)-2)

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

If cos alpha+cos beta=0=sin alpha+sin beta, then prove that cos2 alpha+cos2 beta=-2cos(alpha+beta)

If cos alpha+cos beta=0=sin alpha+sin beta, then prove that cos2 alpha+cos2 beta=-2cos(alpha+beta)

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