נושא : שימוש בזהויות s i n 3 α c o s α − c o s 3 α = tan α ? s i n 2 α ∗ s i n α c o s α ( 1 − c o s 2 α ) = tan α c o s 2 + s i n 2 = tan α s i n 2 α ∗ s i n α c o s α ∗ s i n 2 α = tan α s i n α c o s α = tan α s i n α c o s α = tan α {\displaystyle {\begin{aligned}&{\frac {sin^{3}\alpha }{cos\alpha -cos^{3}\alpha }}=\tan \alpha ?\\&{\frac {sin^{2}\alpha *sin\alpha }{cos\alpha (1-cos^{2}\alpha )}}=\tan \alpha \\&\color {blue}cos^{2}+sin^{2}=\tan \alpha \\&{\frac {sin^{2}\alpha *sin\alpha }{cos\alpha *sin^{2}\alpha }}=\tan \alpha \\&{\frac {sin\alpha }{cos\alpha }}=\tan \alpha \\&\color {blue}{\frac {sin\alpha }{cos\alpha }}=\tan \alpha \\\end{aligned}}}
