There are 1 questions in this calculation: for each question, the 1 derivative of x is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ arctan(\frac{sin(120πt)}{cos(120πt)})\ with\ respect\ to\ x：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( arctan(\frac{sin(120πt)}{cos(120πt)})\right)}{dx}\\=&(\frac{(\frac{cos(120πt)*0}{cos(120πt)} + \frac{sin(120πt)sin(120πt)*0}{cos^{2}(120πt)})}{(1 + (\frac{sin(120πt)}{cos(120πt)})^{2})})\\=&0\\ \end{split}\end{equation} \]

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