[tex] \frac{ \sin(2a) }{1 + \cos(2a) } = \\ [/tex]
[tex] \frac{2 \times \sin(a) \times \cos(a) }{1 \: + \: { \cos}^{2} (a) - { \sin}^{2}(a) } = \\ [/tex]
[tex] \frac{2 \sin(a) \cos(a) }{( \: \: 1 - { \sin }^{2}(a) \: \: ) + { \cos}^{2}(a) } = \\ [/tex]
[tex] \frac{2 \sin(a) \cos(a) }{ { \cos}^{2}(a) + { \cos }^{2}(a) } = \\ [/tex]
[tex] \frac{2 \sin(a) \cos(a) }{2 \cos(a) \cos(a) } = \\ [/tex]
[tex] \frac{ \sin(a) }{ \cos(a) } = \\ [/tex]
[tex] \tan(a) [/tex]
