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

(sin (theta + phi))/( sin theta cos phi) = cot theta tan phi +1.

If 3 tan theta tan phi=1 , then prove that 2 cos (theta+phi)=cos (theta-phi) .

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

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

" If "|{:(sin theta cos phi,,sin theta sin phi,,cos theta),(cos theta cos phi,, cos theta sin phi,,-sin theta),(-sin theta sin phi,,sin theta cos phi,,theta):}| then

Solve cos theta * cos 2 theta * cos 3 theta = (1)/( 4), 0 le theta le pi

Prove that cos 2 theta cos 2 phi + sin ^(2) ( theta - phi) -sin ^(2) (theta + phi) = cos ( 2 theta + 2 phi).

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

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

If cos(theta+phi)=mcos(theta-phi) then tantheta is equal to