if `s=cos^2alpha+cos^2beta` then the value of `cos(alpha+beta).cos(alpha-beta)` in terms of `s` is

if s=cos^(2)alpha+cos^(2)beta then the value of cos(alpha+beta)*cos(alpha-beta) in terms of s is

f(alpha,beta) = cos^2(alpha)+ cos^2(alpha+beta)- 2 cosalpha cosbeta cos(alpha+beta) is

If A = cos ^(2) alpha + cos ^2(alpha + beta)- 2 cos alpha cos beta cos (alpha + beta), then

Let cos(alpha-beta) + cos(beta - gamma) + cos(gamma - alpha)= -3/2 , then the value of cos alpha + cos beta + cos gamma is

If cos alpha + cos beta = 0 = sin alpha + sin beta, then value of cos 2 alpha + cos 2 beta is

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

The expression cos^2(alpha+beta)+cos^2(alpha-beta)-cos2alpha.cos2beta, is

Prove that: cos2alpha\ cos2beta+sin^2(alpha-beta)-sin^2(alpha+beta)=cos2(alpha+beta) .

if alpha and beta satisfy sin alpha cos beta=-(1)/(2), then the greatest value of 2cos alpha sin beta is

If alpha and beta satisfy sin alpha cos beta=-((1)/(2)), then the greatest value of 2cos alpha sin beta is