There are 1 questions in this calculation: for each question, the 3 derivative of x is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ third\ derivative\ of\ function\ \frac{5{x}^{5}}{36} + xcos(x) - 3sin(x)\ with\ respect\ to\ x：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = xcos(x) + \frac{5}{36}x^{5} - 3sin(x)\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( xcos(x) + \frac{5}{36}x^{5} - 3sin(x)\right)}{dx}\\=&cos(x) + x*-sin(x) + \frac{5}{36}*5x^{4} - 3cos(x)\\=& - 2cos(x) - xsin(x) + \frac{25x^{4}}{36}\\\\ &\color{blue}{The\ second\ derivative\ of\ function:} \\&\frac{d\left( - 2cos(x) - xsin(x) + \frac{25x^{4}}{36}\right)}{dx}\\=& - 2*-sin(x) - sin(x) - xcos(x) + \frac{25*4x^{3}}{36}\\=&sin(x) - xcos(x) + \frac{25x^{3}}{9}\\\\ &\color{blue}{The\ third\ derivative\ of\ function:} \\&\frac{d\left( sin(x) - xcos(x) + \frac{25x^{3}}{9}\right)}{dx}\\=&cos(x) - cos(x) - x*-sin(x) + \frac{25*3x^{2}}{9}\\=&xsin(x) + \frac{25x^{2}}{3}\\ \end{split}\end{equation} \]

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