defence exam Army Havildar SAC Mock Test Series 2025 Mathematics Differential Calculus Evaluation of derivatives
If y = \(\rm \cos ^ {-1} \left(\frac {1 - x^2}{1 + x^2}\right) \), then find \(\rm\frac{dy}{dx}\).
1
\(\rm 1\over {1 + x^2}\)
2
\(\rm 2\over {1 + x^2}\)
3
\(\rm 2\over {2 + x^2}\)
4
None of these.