There are 1 questions in this calculation: for each question, the 1 derivative of a is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ (b + s)cos(a) - esin(a)\ with\ respect\ to\ a：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( bcos(a) + scos(a) - esin(a)\right)}{da}\\=&b*-sin(a) + s*-sin(a) - 0sin(a) - ecos(a)\\=&-bsin(a) - ssin(a) - ecos(a)\\ \end{split}\end{equation} \]

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