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

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