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

If sin alpha + sin beta =p , cos alpha + cos beta = q then find the value of cos 2alpha + cos 2beta in terms of p and q.

If cos(theta-alpha)=a and cos(theta-beta)=b then the value of sin^(2)(alpha-beta)+2ab cos(alpha-beta)

If cos (theta - alpha) = a, cos (theta - beta) = b , then the value of sin^(2) (alpha - beta) + 2ab cos (alpha - beta) is

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

sin^(4)alpha+4cos^(4)beta+2=4sqrt(2)sin alpha cos beta;alpha,beta in[0,pi], then cos(alpha+beta)-cos(alpha-beta) is equal to :

If cos^(2)alpha-sin^(2)alpha=tan^(2)beta , then the value of cos^(2)beta-sin^(2)beta is

Prove that |cos alpha-cos beta|<=| alpha-beta|

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