cos2 theta=(1-tan^(2)theta)/(1+tan^(2)theta)

Prove that : cos 2 theta= (1-tan^2 theta)/(1+tan^2 theta) .

If theta=30^@ , verify that: (i) cos2theta=(1-tan^2theta)/(1+tan^2theta) (ii) cos3theta=4cos^3theta-3costheta

If 3cot theta=4 then show that (1-tan^(2)theta)/(1+tan^(2)theta)=(cos^(2)theta-sin^(2)theta)

Prove that (1 - tan^(2) theta)/(1 + tan^(2) theta) = cos^(2) - sin^(2) theta

(tan^(2)(2 theta)-tan^(2)theta)/(1-tan^(2)(2 theta)tan^(2)theta) is equal to-

Prove that (tan^(2)2theta-tan^(2)theta)/(1-tan^(2)2thetatan^(2)theta)=tan 3 theta tan theta .

Prove that (tan^(2)2theta-tan^(2)theta)/(1-tan^(2)2thetatan^(2)theta)=tan 3 theta tan theta .

Prove that (tan^(2)2theta-tan^(2)theta)/(1-tan^(2)2thetatan^(2)theta)=tan 3 theta tan theta .

If theta=30o, verify that: (i) tan2 theta=(2tan theta)/(1-tan^(2)theta)( ii) sin2 theta=(2tan theta)/(1+tan^(2)theta)