There are 1 questions in this calculation: for each question, the 2 derivative of x is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ second\ derivative\ of\ function\ {x}^{2} + arctan(x)\ with\ respect\ to\ x：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = x^{2} + arctan(x)\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( x^{2} + arctan(x)\right)}{dx}\\=&2x + (\frac{(1)}{(1 + (x)^{2})})\\=&2x + \frac{1}{(x^{2} + 1)}\\\\ &\color{blue}{The\ second\ derivative\ of\ function:} \\&\frac{d\left( 2x + \frac{1}{(x^{2} + 1)}\right)}{dx}\\=&2 + (\frac{-(2x + 0)}{(x^{2} + 1)^{2}})\\=& - \frac{2x}{(x^{2} + 1)^{2}} + 2\\ \end{split}\end{equation} \]

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