#### Answer

$-\sin \theta $

#### Work Step by Step

$\dfrac {\tan \left( -\theta \right) }{sec\theta }=\dfrac {\dfrac {\sin \left( -\theta \right) }{\cos \left( -\theta \right) }}{\dfrac {1}{\cos \theta }}=\dfrac {-\sin \theta }{\dfrac {\cos \theta }{\dfrac {1}{\cos \theta }}}=-\sin \theta $