There are 1 questions in this calculation: for each question, the 1 derivative of x is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ sqrt(2)cos(2x)cos(x + 0.785)\ with\ respect\ to\ x：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = cos(2x)cos(x + 0.785)sqrt(2)\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( cos(2x)cos(x + 0.785)sqrt(2)\right)}{dx}\\=&-sin(2x)*2cos(x + 0.785)sqrt(2) - cos(2x)sin(x + 0.785)(1 + 0)sqrt(2) + cos(2x)cos(x + 0.785)*0*0.5*2^{\frac{1}{2}}\\=&-2sin(2x)cos(x + 0.785)sqrt(2) - sin(x + 0.785)cos(2x)sqrt(2)\\ \end{split}\end{equation} \]

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