Find the value of \(\rm \tan^{-1}\left(\frac{\sqrt{1+x}-\sqrt{1-x}}{\sqrt{1+x}+\sqrt{1-x}}\right)\)
1
\(\frac{\pi}{4}+\frac{1}{2}\cos^{-1}x\)
2
\(\frac{\pi}{4}-\frac{1}{2}\cos^{-1}x\)
3
\(-\frac{\pi}{4}+\frac{1}{2}\cos^{-1}x\)
4
\(-\frac{\pi}{4}-\frac{1}{2}\cos^{-1}x\)