The angle between the curve $y=e^{mx}$ and $y=e^{-mx}$ for $m>1 $ is

Question

\[\begin{array}{1 1}(1)\tan^{-1}\bigg(\frac{2m}{m^{2}-1}\bigg)&(2)\tan^{-1}\bigg(\frac{2m}{1-m^{2}}\bigg)\\(3)\tan^{-1}\bigg(\frac{-2m}{1+m^{2}}\bigg)&(4)\tan^{-1}\bigg(\frac{2m}{m^{2}+1}\bigg)\end{array}\]