(22)/(cos^(2)alpha*cos^(2)beta)=tan^(2)beta-tan^(2)alpha

(cos^(2)alpha-cos^(2)beta)/(cos^(2)alpha*cos^(2)beta)=tan^(2)beta-tan^(2)alpha

(cos^2alpha-cos^2beta)/(cos^2alpha cos^2beta)=tan^2beta-tan^2alpha

Prove that (cos^2 alpha - cos^2 beta)/(cos^2 alpha*cos^2 beta) = tan^2 beta - tan^2 alpha

Prove that: tan^(-1){(cos2 alpha sec2 beta+cos2 beta sec2 alpha)/(2)}=tan^(-1){tan^(2)(alpha+beta)tan^(2)(alpha-beta)}+tan

Show that cos^(-1)((cos alpha+cos beta)/(1+cos alpha cos beta))=2tan^(-1)(tan((alpha)/(2))tan((beta)/(2)))

Prove that cos^(-1)[(cos alpha +cos beta)/(1+cos alpha cos beta)]=2tan^(-1)("tan"(alpha)/(2)"tan"(beta)/(2))

Show that cos^(-1) ((cos alpha+cos beta)/(1+cosalpha cosbeta))=2 tan^(-1)(tan (alpha/2) tan (beta/2))

cos2alpha=(3cos2beta-1)/(3-cos2beta) , then tan alpha=

Prove that cos theta =(cos alpha- cos beta)/(1 -cos alpha*cos beta) ⇔ tan theta/2 = pm tan alpha/2 *cot beta/2 .