There are 1 questions in this calculation: for each question, the 1 derivative of y is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ sec(2)(x + y) - 3ysin(yx)\ with\ respect\ to\ y：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = xsec(2) + ysec(2) - 3ysin(xy)\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( xsec(2) + ysec(2) - 3ysin(xy)\right)}{dy}\\=&xsec(2)tan(2)*0 + sec(2) + ysec(2)tan(2)*0 - 3sin(xy) - 3ycos(xy)x\\=&sec(2) - 3sin(xy) - 3xycos(xy)\\ \end{split}\end{equation} \]

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