本次共计算 1 个题目:每一题对 x 求 3 阶导数。
注意,变量是区分大小写的。\[ \begin{equation}\begin{split}【1/1】求函数\frac{x({x}^{2} + 3)}{(3{x}^{2} + 1)} 关于 x 的 3 阶导数:\\\end{split}\end{equation} \]
\[ \begin{equation}\begin{split}\\解:&\\ &原函数 = \frac{x^{3}}{(3x^{2} + 1)} + \frac{3x}{(3x^{2} + 1)}\\&\color{blue}{函数的第 1 阶导数:}\\&\frac{d\left( \frac{x^{3}}{(3x^{2} + 1)} + \frac{3x}{(3x^{2} + 1)}\right)}{dx}\\=&(\frac{-(3*2x + 0)}{(3x^{2} + 1)^{2}})x^{3} + \frac{3x^{2}}{(3x^{2} + 1)} + 3(\frac{-(3*2x + 0)}{(3x^{2} + 1)^{2}})x + \frac{3}{(3x^{2} + 1)}\\=&\frac{-6x^{4}}{(3x^{2} + 1)^{2}} + \frac{3x^{2}}{(3x^{2} + 1)} - \frac{18x^{2}}{(3x^{2} + 1)^{2}} + \frac{3}{(3x^{2} + 1)}\\\\ &\color{blue}{函数的第 2 阶导数:} \\&\frac{d\left( \frac{-6x^{4}}{(3x^{2} + 1)^{2}} + \frac{3x^{2}}{(3x^{2} + 1)} - \frac{18x^{2}}{(3x^{2} + 1)^{2}} + \frac{3}{(3x^{2} + 1)}\right)}{dx}\\=&-6(\frac{-2(3*2x + 0)}{(3x^{2} + 1)^{3}})x^{4} - \frac{6*4x^{3}}{(3x^{2} + 1)^{2}} + 3(\frac{-(3*2x + 0)}{(3x^{2} + 1)^{2}})x^{2} + \frac{3*2x}{(3x^{2} + 1)} - 18(\frac{-2(3*2x + 0)}{(3x^{2} + 1)^{3}})x^{2} - \frac{18*2x}{(3x^{2} + 1)^{2}} + 3(\frac{-(3*2x + 0)}{(3x^{2} + 1)^{2}})\\=&\frac{72x^{5}}{(3x^{2} + 1)^{3}} - \frac{42x^{3}}{(3x^{2} + 1)^{2}} + \frac{6x}{(3x^{2} + 1)} + \frac{216x^{3}}{(3x^{2} + 1)^{3}} - \frac{54x}{(3x^{2} + 1)^{2}}\\\\ &\color{blue}{函数的第 3 阶导数:} \\&\frac{d\left( \frac{72x^{5}}{(3x^{2} + 1)^{3}} - \frac{42x^{3}}{(3x^{2} + 1)^{2}} + \frac{6x}{(3x^{2} + 1)} + \frac{216x^{3}}{(3x^{2} + 1)^{3}} - \frac{54x}{(3x^{2} + 1)^{2}}\right)}{dx}\\=&72(\frac{-3(3*2x + 0)}{(3x^{2} + 1)^{4}})x^{5} + \frac{72*5x^{4}}{(3x^{2} + 1)^{3}} - 42(\frac{-2(3*2x + 0)}{(3x^{2} + 1)^{3}})x^{3} - \frac{42*3x^{2}}{(3x^{2} + 1)^{2}} + 6(\frac{-(3*2x + 0)}{(3x^{2} + 1)^{2}})x + \frac{6}{(3x^{2} + 1)} + 216(\frac{-3(3*2x + 0)}{(3x^{2} + 1)^{4}})x^{3} + \frac{216*3x^{2}}{(3x^{2} + 1)^{3}} - 54(\frac{-2(3*2x + 0)}{(3x^{2} + 1)^{3}})x - \frac{54}{(3x^{2} + 1)^{2}}\\=&\frac{-1296x^{6}}{(3x^{2} + 1)^{4}} + \frac{864x^{4}}{(3x^{2} + 1)^{3}} - \frac{162x^{2}}{(3x^{2} + 1)^{2}} - \frac{3888x^{4}}{(3x^{2} + 1)^{4}} + \frac{1296x^{2}}{(3x^{2} + 1)^{3}} - \frac{54}{(3x^{2} + 1)^{2}} + \frac{6}{(3x^{2} + 1)}\\ \end{split}\end{equation} \]你的问题在这里没有得到解决?请到 热门难题 里面看看吧!