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

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