question_answer

The value of \[\tan \left\{ {{\cos }^{-1}}\left( -\frac{2}{7} \right)-\frac{\pi }{2} \right\}\] is _________.

A)  \[\frac{2}{2\sqrt{5}}\]              

B)  \[\frac{2}{3\sqrt{5}}\]

C)  \[\frac{1}{\sqrt{5}}\]                            

D)  \[\frac{4}{\sqrt{5}}\]

E)  None of these