There are 1 questions in this calculation: for each question, the 1 derivative of x is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ \frac{\frac{21}{2}}{(cos(X)tan(2x))}\ with\ respect\ to\ x：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = \frac{\frac{21}{2}}{cos(X)tan(2x)}\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( \frac{\frac{21}{2}}{cos(X)tan(2x)}\right)}{dx}\\=&\frac{\frac{21}{2}sin(X)*0}{cos^{2}(X)tan(2x)} + \frac{\frac{21}{2}*-sec^{2}(2x)(2)}{cos(X)tan^{2}(2x)}\\=&\frac{-21sec^{2}(2x)}{cos(X)tan^{2}(2x)}\\ \end{split}\end{equation} \]

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