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

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