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。\[ \begin{equation}\begin{split}【1/1】求函数\frac{1}{2}ln(xx + x + 7) 关于 x 的 4 阶导数:\\\end{split}\end{equation} \]
\[ \begin{equation}\begin{split}\\解:&\\ &原函数 = \frac{1}{2}ln(x^{2} + x + 7)\\&\color{blue}{函数的第 1 阶导数:}\\&\frac{d\left( \frac{1}{2}ln(x^{2} + x + 7)\right)}{dx}\\=&\frac{\frac{1}{2}(2x + 1 + 0)}{(x^{2} + x + 7)}\\=&\frac{x}{(x^{2} + x + 7)} + \frac{1}{2(x^{2} + x + 7)}\\\\ &\color{blue}{函数的第 2 阶导数:} \\&\frac{d\left( \frac{x}{(x^{2} + x + 7)} + \frac{1}{2(x^{2} + x + 7)}\right)}{dx}\\=&(\frac{-(2x + 1 + 0)}{(x^{2} + x + 7)^{2}})x + \frac{1}{(x^{2} + x + 7)} + \frac{(\frac{-(2x + 1 + 0)}{(x^{2} + x + 7)^{2}})}{2}\\=&\frac{-2x^{2}}{(x^{2} + x + 7)^{2}} - \frac{2x}{(x^{2} + x + 7)^{2}} + \frac{1}{(x^{2} + x + 7)} - \frac{1}{2(x^{2} + x + 7)^{2}}\\\\ &\color{blue}{函数的第 3 阶导数:} \\&\frac{d\left( \frac{-2x^{2}}{(x^{2} + x + 7)^{2}} - \frac{2x}{(x^{2} + x + 7)^{2}} + \frac{1}{(x^{2} + x + 7)} - \frac{1}{2(x^{2} + x + 7)^{2}}\right)}{dx}\\=&-2(\frac{-2(2x + 1 + 0)}{(x^{2} + x + 7)^{3}})x^{2} - \frac{2*2x}{(x^{2} + x + 7)^{2}} - 2(\frac{-2(2x + 1 + 0)}{(x^{2} + x + 7)^{3}})x - \frac{2}{(x^{2} + x + 7)^{2}} + (\frac{-(2x + 1 + 0)}{(x^{2} + x + 7)^{2}}) - \frac{(\frac{-2(2x + 1 + 0)}{(x^{2} + x + 7)^{3}})}{2}\\=&\frac{8x^{3}}{(x^{2} + x + 7)^{3}} + \frac{12x^{2}}{(x^{2} + x + 7)^{3}} - \frac{6x}{(x^{2} + x + 7)^{2}} + \frac{6x}{(x^{2} + x + 7)^{3}} - \frac{3}{(x^{2} + x + 7)^{2}} + \frac{1}{(x^{2} + x + 7)^{3}}\\\\ &\color{blue}{函数的第 4 阶导数:} \\&\frac{d\left( \frac{8x^{3}}{(x^{2} + x + 7)^{3}} + \frac{12x^{2}}{(x^{2} + x + 7)^{3}} - \frac{6x}{(x^{2} + x + 7)^{2}} + \frac{6x}{(x^{2} + x + 7)^{3}} - \frac{3}{(x^{2} + x + 7)^{2}} + \frac{1}{(x^{2} + x + 7)^{3}}\right)}{dx}\\=&8(\frac{-3(2x + 1 + 0)}{(x^{2} + x + 7)^{4}})x^{3} + \frac{8*3x^{2}}{(x^{2} + x + 7)^{3}} + 12(\frac{-3(2x + 1 + 0)}{(x^{2} + x + 7)^{4}})x^{2} + \frac{12*2x}{(x^{2} + x + 7)^{3}} - 6(\frac{-2(2x + 1 + 0)}{(x^{2} + x + 7)^{3}})x - \frac{6}{(x^{2} + x + 7)^{2}} + 6(\frac{-3(2x + 1 + 0)}{(x^{2} + x + 7)^{4}})x + \frac{6}{(x^{2} + x + 7)^{3}} - 3(\frac{-2(2x + 1 + 0)}{(x^{2} + x + 7)^{3}}) + (\frac{-3(2x + 1 + 0)}{(x^{2} + x + 7)^{4}})\\=&\frac{-48x^{4}}{(x^{2} + x + 7)^{4}} - \frac{96x^{3}}{(x^{2} + x + 7)^{4}} + \frac{48x^{2}}{(x^{2} + x + 7)^{3}} - \frac{72x^{2}}{(x^{2} + x + 7)^{4}} + \frac{48x}{(x^{2} + x + 7)^{3}} - \frac{24x}{(x^{2} + x + 7)^{4}} + \frac{12}{(x^{2} + x + 7)^{3}} - \frac{6}{(x^{2} + x + 7)^{2}} - \frac{3}{(x^{2} + x + 7)^{4}}\\ \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!