There are 1 questions in this calculation: for each question, the 1 derivative of k is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ \frac{-Q{({a}^{2} - \frac{2Qx}{k})}^{\frac{-1}{2}}}{k}\ with\ respect\ to\ k：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = \frac{-Q}{(a^{2} - \frac{2Qx}{k})^{\frac{1}{2}}k}\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( \frac{-Q}{(a^{2} - \frac{2Qx}{k})^{\frac{1}{2}}k}\right)}{dk}\\=&\frac{-(\frac{\frac{-1}{2}(0 - \frac{2Qx*-1}{k^{2}})}{(a^{2} - \frac{2Qx}{k})^{\frac{3}{2}}})Q}{k} - \frac{Q*-1}{(a^{2} - \frac{2Qx}{k})^{\frac{1}{2}}k^{2}}\\=&\frac{Q^{2}x}{(a^{2} - \frac{2Qx}{k})^{\frac{3}{2}}k^{3}} + \frac{Q}{(a^{2} - \frac{2Qx}{k})^{\frac{1}{2}}k^{2}}\\ \end{split}\end{equation} \]

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