There are 1 questions in this calculation: for each question, the 3 derivative of x is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ third\ derivative\ of\ function\ \frac{c{x}^{4}}{12} - dxsin(x) - 2dcos(x)\ with\ respect\ to\ x：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = \frac{1}{12}cx^{4} - dxsin(x) - 2dcos(x)\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( \frac{1}{12}cx^{4} - dxsin(x) - 2dcos(x)\right)}{dx}\\=&\frac{1}{12}c*4x^{3} - dsin(x) - dxcos(x) - 2d*-sin(x)\\=&\frac{cx^{3}}{3} + dsin(x) - dxcos(x)\\\\ &\color{blue}{The\ second\ derivative\ of\ function:} \\&\frac{d\left( \frac{cx^{3}}{3} + dsin(x) - dxcos(x)\right)}{dx}\\=&\frac{c*3x^{2}}{3} + dcos(x) - dcos(x) - dx*-sin(x)\\=&cx^{2} + dxsin(x)\\\\ &\color{blue}{The\ third\ derivative\ of\ function:} \\&\frac{d\left( cx^{2} + dxsin(x)\right)}{dx}\\=&c*2x + dsin(x) + dxcos(x)\\=&2cx + dsin(x) + dxcos(x)\\ \end{split}\end{equation} \]

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