There are 1 questions in this calculation: for each question, the 4 derivative of B is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ 4th\ derivative\ of\ function\ \frac{(sin(b) - sinh(b))}{(cos(b) + cosh(b))}\ with\ respect\ to\ B：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = \frac{sin(b)}{(cos(b) + cosh(b))} - \frac{sinh(b)}{(cos(b) + cosh(b))}\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( \frac{sin(b)}{(cos(b) + cosh(b))} - \frac{sinh(b)}{(cos(b) + cosh(b))}\right)}{dB}\\=&(\frac{-(-sin(b)*0 + sinh(b)*0)}{(cos(b) + cosh(b))^{2}})sin(b) + \frac{cos(b)*0}{(cos(b) + cosh(b))} - (\frac{-(-sin(b)*0 + sinh(b)*0)}{(cos(b) + cosh(b))^{2}})sinh(b) - \frac{cosh(b)*0}{(cos(b) + cosh(b))}\\=& - 0\\\\ &\color{blue}{The\ second\ derivative\ of\ function:} \\&\frac{d\left( - 0\right)}{dB}\\=& - 0\\\\ &\color{blue}{The\ third\ derivative\ of\ function:} \\&\frac{d\left( - 0\right)}{dB}\\=& - 0\\\\ &\color{blue}{The\ 4th\ derivative\ of\ function:} \\&\frac{d\left( - 0\right)}{dB}\\=& - 0\\ \end{split}\end{equation} \]

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