`If sin 2 alpha + sin 2 beta = 3 "and" cos 2 alpha + cos 2 beta = 4,"then"-`
` cos2 (alpha + beta)=`

If sin 2 alpha + sin 2 beta = 3 "and" cos 2 alpha + cos 2 beta = 4,"then"- sin 2 ( alpha + beta)

If sin 2 alpha + sin 2 beta = 3 "and" cos 2 alpha + cos 2 beta = 4,"then"- tan2 (alpha + beta)=

2 sin ^(2) beta + 4 cos (alpha + beta) sin alpha sin beta + cos 2 (alpha + beta )=

If sin (theta + alpha) = a and sin (theta + beta) = b,"then" cos 2 (alpha - beta) - 4ab cos (alpha - beta) =

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

2 sin^(2) beta + 4 cos( alpha+ beta) sin alpha sin beta + cos ( 2 alpha + 2 beta )=

(cos alpha + cos beta) ^ (2) + (sin alpha + sin beta) ^ (2) =