JEE Physics Practice Question

Two vectors $${\overrightarrow P }$$ and $${\overrightarrow Q }$$ have equal magnitudes. If the magnitude of $${\overrightarrow P + \overrightarrow Q }$$ is n times the magnitude of $${\overrightarrow P - \overrightarrow Q }$$, then angle between $${\overrightarrow P }$$ and $${\overrightarrow Q }$$ is :

1. A.$${\sin ^{ - 1}}\left( {{{n - 1} \over {n + 1}}} \right)$$
2. B.$${\cos ^{ - 1}}\left( {{{n - 1} \over {n + 1}}} \right)$$
3. C.$${\sin ^{ - 1}}\left( {{{{n^2} - 1} \over {{n^2} + 1}}} \right)$$
4. D.$${\cos ^{ - 1}}\left( {{{{n^2} - 1} \over {{n^2} + 1}}} \right)$$