There are 1 questions in this calculation: for each question, the 1 derivative of x is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ -21.65cos(x)cos(3x) + 64.95sin(3x)sin(x) - 10sin(x)\ with\ respect\ to\ x：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( -21.65cos(x)cos(3x) + 64.95sin(3x)sin(x) - 10sin(x)\right)}{dx}\\=&-21.65*-sin(x)cos(3x) - 21.65cos(x)*-sin(3x)*3 + 64.95cos(3x)*3sin(x) + 64.95sin(3x)cos(x) - 10cos(x)\\=&21.65sin(x)cos(3x) + 64.95sin(3x)cos(x) + 194.85sin(x)cos(3x) + 64.95sin(3x)cos(x) - 10cos(x)\\ \end{split}\end{equation} \]

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