If `x = sin alpha, y = sin beta, z = sin (alpha+beta)` then `cos(alpha+beta)=`

If x= sin alpha + sin betga , y = cos alpha + cos beta tan alpha + tan beta =

(cos alpha + cos beta)/( sin alpha - sin beta) + (sin alpha + sin beta)/( cos alpha - cos beta ) =

If x cos alpha + y sin alpha = x cos beta + y sin beta = 2a then cos alpha cos beta =

sin alpha + sin beta = a "and" cos alpha + cos beta = b sin (alpha + beta) =

sin alpha + sin beta = a, cos alpha + cos beta = b rArr sin (alpha + beta)

If sin alpha + sin beta = a , cos alpha + cos beta = b " then sin ( alpha + beta ) =

If x cos alpha + y sin alpha = x cos beta + y sin beta "then" (2(1-cos (alpha - beta)))/(cos beta - cos alpha)^(2)=

If x cos alpha + y sin alpha = x cos beta + y sin beta "then" "tan" (alpha + beta)/2=