Find the second order derivatives of the functions given.
`tan^(-1)x`.

Explanation

To find the second order derivative of the function \( y = \tan^{-1}(x) \), we can follow these steps:

### Step 1: Find the first derivative \( y' \)
The first derivative of \( y = \tan^{-1}(x) \) can be found using the derivative formula for the inverse tangent function:

\[ y' = \frac{d}{dx}(\tan^{-1}(x)) = \frac{1}{1 + x^2} \]
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