If `0lttheta,philtpi and cosphi+costheta-cos(theta+phi)=3/2` prove that `theta=phi= pi/3.`

If 0

If 0 lt theta , phi lt pi and 8 cos theta cos phi cos (theta + phi)+1=0 find theta and phi

If 3tan theta tan phi=1 then (cos(theta-phi))/(cos(theta+phi)) is

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

cos theta=4/5, cos phi=3/5 then cos((theta-phi)/2)=

3tanthetatanphi=1 , then (cos(theta-phi))/(cos(theta+phi))=?

If sin theta+sin phi=sqrt(3)(cos phi-cos theta)), prove that sin3 theta+sin3 phi=0

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

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

If cos(theta+phi)= mcos(theta-phi) , then prove that tan theta=(1-m)/(1+m)cotphi .