If `sin theta +sin phi=a` and `cos theta +cos phi =b` then prove `cos (theta +phi)=(b^(2)-a^(2))/(b^(2)+a^(2))`

If sin theta - sin phi = a and cos theta + cos phi = b then prove that cos(theta + phi) = (a^(2)+b^(2) -2)/2

If sin theta+sin phi=a and cos theta+cos phi=b find the value of tan((theta-phi)/(2))

If sin 2 theta + sin 2 phi =1/2 and cos 2 theta + cos 2 phi =3/2, then cos ^(2) (theta - phi)=

If sin 2theta+sin 2phi=1//2 and cos2theta+cos 2phi=3//2 , then cos^(2)(theta-phi)=

If cos theta+cos phi=a and sin theta - sin phi=b , then: 2cos(theta + phi) =

If sim 2theta+sin2phi=1/2 and cos 2theta+cos2phi=3/2 then cos^2(theta-phi)=

sin theta + sin phi = a, cos theta + cos phi = b then prove tan [(theta-phi) / (2)] = + - sqrt ((4-a ^ (2) -b ^ (2)) / (a ^ (2) + b ^ (2)))

If sin2 theta+sin2 phi=(1)/(2) and cos2 theta+cos2 phi=(3)/(2), then cos^(2)(theta-phi)=

If sin theta+sin phi=(1)/(2) and cos theta+cos phi=1 then find the value of cot((theta+phi)/(2))

If sin theta+sin phi=(1)/(4) and cos theta+cos phi=(1)/(5) then value of sin(theta+phi) is