There are 1 questions in this calculation: for each question, the 1 derivative of D is calculated.
    Note that variables are case sensitive.
\[ \begin{equation}\begin{split}[1/1]Find\ the\ first\ derivative\ of\ function\ \frac{1}{2}D + \frac{1}{2}d + sqrt((D + H - h)(d - H + h))\ with\ respect\ to\ D：\\\end{split}\end{equation} \]\[ \begin{equation}\begin{split}\\Solution:&\\ &Primitive\ function\ = \frac{1}{2}D + \frac{1}{2}d + sqrt(dD - HD + hD + dH + 2Hh - H^{2} - dh - h^{2})\\&\color{blue}{The\ first\ derivative\ function：}\\&\frac{d\left( \frac{1}{2}D + \frac{1}{2}d + sqrt(dD - HD + hD + dH + 2Hh - H^{2} - dh - h^{2})\right)}{dD}\\=&\frac{1}{2} + 0 + \frac{(d - H + h + 0 + 0 + 0 + 0 + 0)*\frac{1}{2}}{(dD - HD + hD + dH + 2Hh - H^{2} - dh - h^{2})^{\frac{1}{2}}}\\=&\frac{d}{2(dD - HD + hD + dH + 2Hh - H^{2} - dh - h^{2})^{\frac{1}{2}}} - \frac{H}{2(dD - HD + hD + dH + 2Hh - H^{2} - dh - h^{2})^{\frac{1}{2}}} + \frac{h}{2(dD - HD + hD + dH + 2Hh - H^{2} - dh - h^{2})^{\frac{1}{2}}} + \frac{1}{2}\\ \end{split}\end{equation} \]

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