There are 1 questions in this calculation: for each question, the 1 derivative of x is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ {(rcos(a) + 2rsin(a))}^{2}\ with\ respect\ to\ x：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = r^{2}cos^{2}(a) + 4r^{2}sin(a)cos(a) + 4r^{2}sin^{2}(a)\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( r^{2}cos^{2}(a) + 4r^{2}sin(a)cos(a) + 4r^{2}sin^{2}(a)\right)}{dx}\\=&r^{2}*-2cos(a)sin(a)*0 + 4r^{2}cos(a)*0cos(a) + 4r^{2}sin(a)*-sin(a)*0 + 4r^{2}*2sin(a)cos(a)*0\\=&0\\ \end{split}\end{equation} \]

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