本次共计算 1 个题目:每一题对 x 求 4 阶导数。
注意,变量是区分大小写的。\[ \begin{equation}\begin{split}【1/1】求函数x(x - 9){(x - 9)}^{-1} 关于 x 的 4 阶导数:\\\end{split}\end{equation} \]
\[ \begin{equation}\begin{split}\\解:&\\ &原函数 = \frac{x^{2}}{(x - 9)} - \frac{9x}{(x - 9)}\\&\color{blue}{函数的第 1 阶导数:}\\&\frac{d\left( \frac{x^{2}}{(x - 9)} - \frac{9x}{(x - 9)}\right)}{dx}\\=&(\frac{-(1 + 0)}{(x - 9)^{2}})x^{2} + \frac{2x}{(x - 9)} - 9(\frac{-(1 + 0)}{(x - 9)^{2}})x - \frac{9}{(x - 9)}\\=&\frac{-x^{2}}{(x - 9)^{2}} + \frac{2x}{(x - 9)} + \frac{9x}{(x - 9)^{2}} - \frac{9}{(x - 9)}\\\\ &\color{blue}{函数的第 2 阶导数:} \\&\frac{d\left( \frac{-x^{2}}{(x - 9)^{2}} + \frac{2x}{(x - 9)} + \frac{9x}{(x - 9)^{2}} - \frac{9}{(x - 9)}\right)}{dx}\\=&-(\frac{-2(1 + 0)}{(x - 9)^{3}})x^{2} - \frac{2x}{(x - 9)^{2}} + 2(\frac{-(1 + 0)}{(x - 9)^{2}})x + \frac{2}{(x - 9)} + 9(\frac{-2(1 + 0)}{(x - 9)^{3}})x + \frac{9}{(x - 9)^{2}} - 9(\frac{-(1 + 0)}{(x - 9)^{2}})\\=&\frac{2x^{2}}{(x - 9)^{3}} - \frac{4x}{(x - 9)^{2}} - \frac{18x}{(x - 9)^{3}} + \frac{18}{(x - 9)^{2}} + \frac{2}{(x - 9)}\\\\ &\color{blue}{函数的第 3 阶导数:} \\&\frac{d\left( \frac{2x^{2}}{(x - 9)^{3}} - \frac{4x}{(x - 9)^{2}} - \frac{18x}{(x - 9)^{3}} + \frac{18}{(x - 9)^{2}} + \frac{2}{(x - 9)}\right)}{dx}\\=&2(\frac{-3(1 + 0)}{(x - 9)^{4}})x^{2} + \frac{2*2x}{(x - 9)^{3}} - 4(\frac{-2(1 + 0)}{(x - 9)^{3}})x - \frac{4}{(x - 9)^{2}} - 18(\frac{-3(1 + 0)}{(x - 9)^{4}})x - \frac{18}{(x - 9)^{3}} + 18(\frac{-2(1 + 0)}{(x - 9)^{3}}) + 2(\frac{-(1 + 0)}{(x - 9)^{2}})\\=&\frac{-6x^{2}}{(x - 9)^{4}} + \frac{12x}{(x - 9)^{3}} + \frac{54x}{(x - 9)^{4}} - \frac{54}{(x - 9)^{3}} - \frac{6}{(x - 9)^{2}}\\\\ &\color{blue}{函数的第 4 阶导数:} \\&\frac{d\left( \frac{-6x^{2}}{(x - 9)^{4}} + \frac{12x}{(x - 9)^{3}} + \frac{54x}{(x - 9)^{4}} - \frac{54}{(x - 9)^{3}} - \frac{6}{(x - 9)^{2}}\right)}{dx}\\=&-6(\frac{-4(1 + 0)}{(x - 9)^{5}})x^{2} - \frac{6*2x}{(x - 9)^{4}} + 12(\frac{-3(1 + 0)}{(x - 9)^{4}})x + \frac{12}{(x - 9)^{3}} + 54(\frac{-4(1 + 0)}{(x - 9)^{5}})x + \frac{54}{(x - 9)^{4}} - 54(\frac{-3(1 + 0)}{(x - 9)^{4}}) - 6(\frac{-2(1 + 0)}{(x - 9)^{3}})\\=&\frac{24x^{2}}{(x - 9)^{5}} - \frac{48x}{(x - 9)^{4}} - \frac{216x}{(x - 9)^{5}} + \frac{216}{(x - 9)^{4}} + \frac{24}{(x - 9)^{3}}\\ \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!