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

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