defence exam Army Havildar SAC Mock Test Series 2025 Mathematics Differential Calculus Evaluation of derivatives
अगर y = \(\rm \cos ^ {-1} \left(\frac {1 - x^2}{1 + x^2}\right) \) तो \(\rm\frac{dy}{dx}\) ज्ञात कीजिए।
1
\(\rm 1\over {1 + x^2}\)
2
\(\rm 2\over {1 + x^2}\)
3
\(\rm 2\over {2 + x^2}\)
4
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