Tg^2 2x-tg^2 x/1-tg^2 2x tg^2 x=tg 3x tg x

Question

Tg^2 2x-tg^2 x/1-tg^2 2x tg^2 x=tg 3x tg x

Answer 1

[(tg2x+tgx)/(1-tg2xtgx)]*[(tg2x-tgx)/(1+tg2xtgx)]=tg3x*tgx
tg3xtgx=tg3xtgx