Respuesta :

[tex]r = 3sec( \alpha ) \\ r = \frac{3}{cos( \alpha )} [/tex]

[tex]x = rcos( \alpha ) \: \: \: \: \: \: \: cos( \alpha ) = \frac{x}{r} [/tex]

[tex]r = \frac{3}{ \frac{x}{r} } \\ r = \frac{3r}{x} \: \: \: \: \: \: x = 3 \\ line[/tex]