prove that `2tan^-1(sqrt((a-b)/(a+b))tan(theta/2))`=`cos^-1((acostheta+b)/(a+bcostheta))`

2tan^(-1)(sqrt((a-b)/(a+b))tan((theta)/(2)))=cos^(-1)((a cos theta+b)/(a+b cos theta))

prove that 2tan^(-1)(sqrt((a-b)/(a+b))tan((theta)/(2)))=cos^(-1)((a cos theta+b)/(a+b cos theta))

The value 2tan^(-1)[sqrt((a-b)/(a+b))(tan theta)/(2)] is equal to cos^(-1)((a cos theta+b)/(a+b cos theta))(b)cos^(-1)((a+b cos theta)/(a cos theta+b))cos^(-1)((a cos theta)/(a+b cos theta)) (d) cos^(-1)((b cos theta)/(a cos theta+b))

Prove that 2tan^(-1)sqrt((b)/(a))=cos^(-1)((a-b)/(a+b))

Prove that : (1 - tan^(2) theta)/(1 + tan^(2) theta) = cos^(2) theta - sin^(2) 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 tan theta.tan phi = sqrt ((a -b)/(a +b)), then (a -b cos 2 theta)(a -b cos 2 phi) is

tan theta.tan phi=sqrt((a-b)/(a+b)), then (a-b cos2 theta)(a-b cos2 phi)=