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

Prove that (cos2theta)/(1+sin2theta)=tan(pi//4-theta)

Prove that (costheta)/(1+sintheta)=tan((pi)/(4)-(theta)/(2))

(ii)Find the value of tan(pi/4+theta)tan(pi/4-theta)

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

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

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

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

If (-pi)/(2) lt theta lt (pi)/(2) and theta ne +- (pi)/(4) , then the value of cot((pi)/(4) + theta)cot((pi)/(4)-theta) is

tan ((pi)/(4)+(theta)/(2))+tan ((pi)/(4)-(theta)/(2)) is equal to