If `sin alpha+sin beta=a\ a n d\ cosalpha+cosbeta=b ,` show that : `sin(alpha+beta)=(2"a b")/(a^2+b^2)`

If sin alpha+sin beta=a\ a n d\ cosalpha+cosbeta=b , show that : cos(alpha+beta)=(b^2-a^2)/(b^2+a^2)

If sin alpha + sin beta = a and cos alpha + cos beta = b, prove that : cos (alpha-beta) = 1/2 (a^2 + b^2 -2)

If sin alpha+sin beta=a\ a n d\ cosalpha-cosbeta=b , then tan(alpha-beta)/2= -a/b b. b/a c. sqrt(a^2+b^2) d. none of these

If sinalpha+sinbeta=a and cosalpha+cosbeta=b prove that: cos(alpha-beta)=((a^2+b^2-2)/2)

If sinalpha+sinbeta=a and cosalpha+cosbeta=b prove that: cos(alpha-beta)=((a^2+b^2-2)/2)

If sin alpha + sin beta=a and cos alpha+cosbeta=b then tan((alpha-beta)/2) is equal to

If sin alpha+sin beta=a and cos alpha-cos beta=b then tan((alpha-beta)/2) is equal to-

If sinalpha-sinbeta=a and cosalpha+cosbeta=b then write the value of "cos"(alpha+beta) .

If sinalpha+sinbeta=a and cosalpha+cosbeta=b , prove that tan((alpha-beta)/2)=+-sqrt((4-a^2-b^2)/(a^2+b^2)) .

If sinalpha+sinbeta=a and cosalpha+cosbeta=b , prove that tan((alpha-beta)/2)=+-sqrt((4-a^2-b^2)/(a^2+b^2)) .