There are 1 questions in this calculation: for each question, the 2 derivative of x is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ second\ derivative\ of\ function\ \frac{2{x}^{2}}{({x}^{2} + {y}^{2})}\ with\ respect\ to\ x：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = \frac{2x^{2}}{(x^{2} + y^{2})}\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( \frac{2x^{2}}{(x^{2} + y^{2})}\right)}{dx}\\=&2(\frac{-(2x + 0)}{(x^{2} + y^{2})^{2}})x^{2} + \frac{2*2x}{(x^{2} + y^{2})}\\=&\frac{-4x^{3}}{(x^{2} + y^{2})^{2}} + \frac{4x}{(x^{2} + y^{2})}\\\\ &\color{blue}{The\ second\ derivative\ of\ function:} \\&\frac{d\left( \frac{-4x^{3}}{(x^{2} + y^{2})^{2}} + \frac{4x}{(x^{2} + y^{2})}\right)}{dx}\\=&-4(\frac{-2(2x + 0)}{(x^{2} + y^{2})^{3}})x^{3} - \frac{4*3x^{2}}{(x^{2} + y^{2})^{2}} + 4(\frac{-(2x + 0)}{(x^{2} + y^{2})^{2}})x + \frac{4}{(x^{2} + y^{2})}\\=&\frac{16x^{4}}{(x^{2} + y^{2})^{3}} - \frac{20x^{2}}{(x^{2} + y^{2})^{2}} + \frac{4}{(x^{2} + y^{2})}\\ \end{split}\end{equation} \]

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