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

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