[" 15.If "x=cos alpha+i sin alpha" and "y=cos beta+i sin beta" ,prove that "],[qquad (x-y)/(x+y)=i tan(alpha-beta)/(2)]

If x= cos alpha+ i sin alpha, y = cos beta+ i sin beta, then prove that (x-y)/(x+y) =i (tan )(alpha-beta)/2

If x=cos alpha+i sin alpha,y=cos beta+i sin beta then prove that (x-y)/(x+y)=i(tan)(alpha-beta)/(2)

If x=cos alpha+i sin alpha,y=cos beta+isinbeta, then x/y-y/x=

If x=cos alpha+i sin alpha,y=cos beta+isinbeta, then (x-y)/(x+y)=

If x=cos alpha+i sin alpha, y=cos beta+i sin beta then " (y)/(x)-(x)/(y)=

If x = cos alpha + i sin alpha , y = cos beta + i sin beta , prove that x^(m)y^(n)+1/(x^m y^n) = 2 cos (m alpha + n beta) .

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

If x cos alpha + y sin alpha=x cos beta+y sin beta,"show that",y=x "tan"(alpha+beta)/2

If x cos alpha + y sin alpha = x cos beta + y sin beta = a, 0