question_answer

The range of values of 'a' such that the angle \[\theta \] between the pair of tangents drawn from the point (a, 0) to the circle \[{{x}^{2}}+{{y}^{2}}=1\] satisfies \[\frac{\pi }{2}<\theta <\pi \] is:

A) \[(1,\,\,2)\]                     

B) \[(1,\,\,\sqrt{2})\]

C) \[(-\sqrt{2},\,\,-1)\]

D) \[(-\sqrt{2},\,\,-1)\cup (1,\,\,\sqrt{2})\]