Тригонометрия

[Гост]

Само това ми остана. Благодаря предварително !!!

[math10.com]

[tex]\frac{cos^2{2\alpha}-1}{sin^6 \alpha -1+cos^6\alpha}=[/tex]

[tex]=\frac{\cancel{cos^2{2\alpha}}-sin ^2{2\alpha}-\cancel{cos^2{2\alpha}} }{(sin^2 \alpha +cos^2\alpha)(sin^4 \alpha -sin^2 \alpha.cos^2\alpha+cos^4\alpha)-1}=[/tex]

[tex]=\frac{-(2sin \alpha.cos\alpha)^2}{(sin^2 \alpha +cos^2\alpha)^2-3sin^2 \alpha.cos^2\alpha-1}=[/tex]

[tex]=\frac{-4\cancel{sin^2 \alpha.cos^2 \alpha}}{-3\cancel{sin^2 \alpha.cos^2\alpha}}=[/tex]

[tex]=\frac{4}{3}[/tex]

[Гост]

Благодаря