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

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