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

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