(clas5-11)/(10)+tan(theta)/(2)=sqrt((1-varepsilon)/(1+0))tan(phi)/(2)" then prove "cos phi=(cos theta)/(2)

If tan[(theta)/(2)]=sqrt((1-e)/(1+e))tan[(phi)/(2)] then prove that cos phi=(cos theta-e)/(1-e cos theta)

If tan (theta/2) = sqrt((1-e)/(1+e)) tan(phi/2) ,then show that cos phi=(cos theta-e)/(1-ecos theta) .

If tan (phi /2)= sqrt((1+a)/(1-a)) tan"" theta/2," then prove that cos "phi=(cos theta-a)/(1-a cos theta)

If tan(theta)/(2)=sqrt((a-b)/(a+b))tan(phi)/(2), prove that cos theta=(a cos phi+b)/(a+b cos phi)

If sqrt(a + b) tan = theta/2 = sqrt(a -b) tan phi/2 then prove that a + b cos phi = (a cos phi+ b) sec theta .

If tan((theta)/(2))=5/2and tan((phi)/(2))=3/4, the value of cos(theta+phi), is

If tan((theta)/(2))=5/2and tan((phi)/(2))=3/4, the value of cos(theta+phi), is

If tan^(2)theta=1+2tan^(2)phi, prove that cos2 phi=1+2cos2 theta

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