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

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