Two vectors $\vec { A }$ and $\vec { B }$ have equal magnitudes. If magnitude of $\vec { A } + \vec { B }$ is equal to two times the magnitude of $\vec { A } - \vec { B }$, then the angle between $\vec { A }$ and $\vec { B }$ will be\\
(1) $\cos ^ { - 1 } \left( \frac { 3 } { 5 } \right)$\\
(2) $\cos ^ { - 1 } \left( \frac { 1 } { 3 } \right)$\\
(3) $\sin ^ { - 1 } \left( \frac { 1 } { 3 } \right)$\\
(4) $\sin ^ { - 1 } \left( \frac { 3 } { 5 } \right)$