Explicación paso a paso:
tana*csc*=[tex]\frac{sen(a)}{cos(a)}\cdot \frac{1}{sen(a)}=\\\frac{1}{cos(a)}=sec (a)\\\\\\\frac{tan(\alpha)}{cot(\alpha)}=\frac{tan\alpha}{\frac{1}{tan\alpha}}=tan^2\alpha\\\\\\cosa \cdot tana = cosa \cdot \frac{sena}{cosa} = sena\\\\\\\frac{tan\alpha}{sen\alpha}=\frac{\frac{sen\alpha}{cos\alpha}}{sen\alpha}=\frac{sen\alpha}{cos\alpha sen \alpha} = \frac{1}{cos \alpha}[/tex]
