Question

Решить:
sin^2(-330°)-cos^2(-120°)-tg^2(-240°)-ctg^2(-330°)=

Answer 1

sin^2(-330°)-cos^2(-120°)-tg^2(-240°)-ctg^2(-330°)=
=sin^2(30)-cos^2(60)-tg^2(60)-ctg^2(30)=
=sin^2(30)-sin^2(30-2tg^2(60)=-6