1)[tex]tg(x) + ctg(x) + tg^{2} (x) + ctg^{2}(x) +tg^{3}(x) +ctg^{3}(x) = 6[/tex]

2)[tex]cos(2\alpha ) = 3(sin^{3}(\alpha ) +cos^{3} (\alpha) ) [/tex]