`(cosalpha-cosbeta)^(2)+(sinalpha-sinbeta)^(2)=4sin^(2)((alpha-beta)/(2))`.

Prove that (cosalpha+cosbeta)^2+(sinalpha+sinbeta)^2=4cos^2((alpha-beta)/2) .

Prove that: (cosalpha+cosbeta)^2+(sinalpha+sinbeta)^2=4cos^2((alpha-beta)/2)

Prove that: (cosalpha+cosbeta)^2+(sinalpha+sinbeta)^2=4cos^2((alpha-beta)/2)

Prove that (cosalpha+cosbeta)^2+(sinalpha+sinbeta)^2=4cos^2((alpha-beta)/2)dot

Prove that (cosalpha+cosbeta)^2+(sinalpha+sinbeta)^2=4cos^2((alpha-beta)/2)dot

Prove that: (cosalpha+cosbeta)^2+(sinalpha+sinbeta)^2=4cos^2\ \ ((alpha-beta)/2)

If (cosalpha+cosbeta)^2+(sinalpha+sinbeta)^2=lambdacos^2((alpha-beta)/2), write the value of lambdadot

(cosalpha+cosbeta)^2+(sinalpha+sinbeta)^2= ............... A) 4 cos ^(2) ((alpha - beta)/(2)) B) 4 sin ^(2) ((alpha - beta)/( 2)) C) 4 cos ^(2) ((alpha + beta)/(2)) D) 4 sin ^(2) ((alpha +beta)/(2))

If cosalpha+cosbeta=1/3 and sinalpha+sinbeta=1/4 ,show that tan ((alpha+beta)/2)=3/4

If cosalpha+cosbeta=1/3 and sinalpha+sinbeta=1/4 prove that cos(alpha-beta)/2=+-5/24