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

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