$\frac{d}{d x}\left\{\left(1+x^2\right) \tan ^{-1}(x)\right\}=$
$\frac{d}{d x}\left\{\left(1+x^2\right) \tan ^{-1}(x)\right\}=$
- $x \tan ^{-1}(x)$
- $2 \tan ^{-1}(x)$
- $2 x \tan ^{-1}(x)+1$
- $x \tan ^{-1}(x)+1$
Solution
We have,
$
\begin{gathered}
\frac{d}{d x}(u \cdot v)=u \cdot \frac{d v}{d x}+v \cdot \frac{d v}{d x} \\
\frac{d}{d x}\left[(1+x)^2 \cdot \tan ^{-1}(x)\right]=\left(1+x^2\right) \\
\frac{d}{d x} \tan ^{-1} x+\frac{d}{d x}\left(1+x^2\right) \cdot \tan ^{-1} x \\
=\left(1+x^2\right) \cdot \frac{1}{1+x^2}+(2 x) \cdot \tan ^{-1} x \\
=1+2 x \tan ^{-1} x=2 x \tan ^{-1} x+1
\end{gathered}
$
Hence, option (3) is correct
Asked in: AP EAMCET 2020 (22 Sep Shift 2)
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