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

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