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

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