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

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