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

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