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

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