Prove that `tantheta+tan(60^(@)+theta)+tan(120^(@)+theta)=3tan3theta`.

Prove that (tan^(2)2theta-tan^(2)theta)/(1-tan^(2)2thetatan^(2)theta)=tan3thetatantheta .

(ii)Prove that tan(pi/4-theta)=(1-tan theta)/(1+tan theta)

Prove that tan((pi)/(4)+theta)-tan((pi)/(4)-theta)=2tan2theta .

Prove that cottheta-tantheta=2cot2theta .

Prove that tan70^@=tan20^@+2tan50^@

Prove that (tan5theta+tan3theta)/(tan5theta-tan3theta)=4cos2thetacos4theta

If theta=pi//4n , then the value of tan(theta) tan (2theta).....tan(2n-2)thetatan(2n-1)theta is

Prove that tan20^(@)tan40^(@)tan80^(@)=tan60^(@) .

Prove that (sec8theta-1)/(sec4theta-1)=(tan8theta)/(tan2theta)

Show that [[1 , -tan theta ],[ tan theta, 1]][[1, tan theta],[ -tan theta, 1]]^(-1)=[[cos 2 theta, -sin 2 theta],[ sin 2 theta, cos 2 theta]]