There are 1 questions in this calculation: for each question, the 1 derivative of x is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ xf{(x)}^{3} + 3{x}^{5}f(x)\ with\ respect\ to\ x：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = fx^{4} + 3fx^{6}\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( fx^{4} + 3fx^{6}\right)}{dx}\\=&f*4x^{3} + 3f*6x^{5}\\=&4fx^{3} + 18fx^{5}\\ \end{split}\end{equation} \]

Your problem has not been solved here? Please take a look at the  hot problems ！