There are 1 questions in this calculation: for each question, the 1 derivative of x is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ 15tanh(\frac{1}{5}x) - 5tanh(\frac{3}{10}x - 15) + 5tanh(\frac{1}{5}x - 18)\ with\ respect\ to\ x：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( 15tanh(\frac{1}{5}x) - 5tanh(\frac{3}{10}x - 15) + 5tanh(\frac{1}{5}x - 18)\right)}{dx}\\=&15sech^{2}(\frac{1}{5}x)*\frac{1}{5} - 5sech^{2}(\frac{3}{10}x - 15)(\frac{3}{10} + 0) + 5sech^{2}(\frac{1}{5}x - 18)(\frac{1}{5} + 0)\\=&3sech^{2}(\frac{1}{5}x) - \frac{3sech^{2}(\frac{3}{10}x - 15)}{2} + sech^{2}(\frac{1}{5}x - 18)\\ \end{split}\end{equation} \]

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