There are 1 questions in this calculation: for each question, the 1 derivative of x is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ \frac{5x}{(1200 + x)}\ with\ respect\ to\ x：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = \frac{5x}{(x + 1200)}\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( \frac{5x}{(x + 1200)}\right)}{dx}\\=&5(\frac{-(1 + 0)}{(x + 1200)^{2}})x + \frac{5}{(x + 1200)}\\=&\frac{-5x}{(x + 1200)^{2}} + \frac{5}{(x + 1200)}\\ \end{split}\end{equation} \]

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