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。\[ \begin{equation}\begin{split}【1/1】求函数\frac{1}{(a{x}^{2} + bx + c)} 关于 x 的 4 阶导数:\\\end{split}\end{equation} \]
\[ \begin{equation}\begin{split}\\解:&\\ &原函数 = \frac{1}{(ax^{2} + bx + c)}\\&\color{blue}{函数的第 1 阶导数:}\\&\frac{d\left( \frac{1}{(ax^{2} + bx + c)}\right)}{dx}\\=&(\frac{-(a*2x + b + 0)}{(ax^{2} + bx + c)^{2}})\\=&\frac{-2ax}{(ax^{2} + bx + c)^{2}} - \frac{b}{(ax^{2} + bx + c)^{2}}\\\\ &\color{blue}{函数的第 2 阶导数:} \\&\frac{d\left( \frac{-2ax}{(ax^{2} + bx + c)^{2}} - \frac{b}{(ax^{2} + bx + c)^{2}}\right)}{dx}\\=&-2(\frac{-2(a*2x + b + 0)}{(ax^{2} + bx + c)^{3}})ax - \frac{2a}{(ax^{2} + bx + c)^{2}} - (\frac{-2(a*2x + b + 0)}{(ax^{2} + bx + c)^{3}})b + 0\\=&\frac{8a^{2}x^{2}}{(ax^{2} + bx + c)^{3}} + \frac{8abx}{(ax^{2} + bx + c)^{3}} - \frac{2a}{(ax^{2} + bx + c)^{2}} + \frac{2b^{2}}{(ax^{2} + bx + c)^{3}}\\\\ &\color{blue}{函数的第 3 阶导数:} \\&\frac{d\left( \frac{8a^{2}x^{2}}{(ax^{2} + bx + c)^{3}} + \frac{8abx}{(ax^{2} + bx + c)^{3}} - \frac{2a}{(ax^{2} + bx + c)^{2}} + \frac{2b^{2}}{(ax^{2} + bx + c)^{3}}\right)}{dx}\\=&8(\frac{-3(a*2x + b + 0)}{(ax^{2} + bx + c)^{4}})a^{2}x^{2} + \frac{8a^{2}*2x}{(ax^{2} + bx + c)^{3}} + 8(\frac{-3(a*2x + b + 0)}{(ax^{2} + bx + c)^{4}})abx + \frac{8ab}{(ax^{2} + bx + c)^{3}} - 2(\frac{-2(a*2x + b + 0)}{(ax^{2} + bx + c)^{3}})a + 0 + 2(\frac{-3(a*2x + b + 0)}{(ax^{2} + bx + c)^{4}})b^{2} + 0\\=&\frac{-48a^{3}x^{3}}{(ax^{2} + bx + c)^{4}} - \frac{72a^{2}bx^{2}}{(ax^{2} + bx + c)^{4}} + \frac{24a^{2}x}{(ax^{2} + bx + c)^{3}} - \frac{36ab^{2}x}{(ax^{2} + bx + c)^{4}} + \frac{12ab}{(ax^{2} + bx + c)^{3}} - \frac{6b^{3}}{(ax^{2} + bx + c)^{4}}\\\\ &\color{blue}{函数的第 4 阶导数:} \\&\frac{d\left( \frac{-48a^{3}x^{3}}{(ax^{2} + bx + c)^{4}} - \frac{72a^{2}bx^{2}}{(ax^{2} + bx + c)^{4}} + \frac{24a^{2}x}{(ax^{2} + bx + c)^{3}} - \frac{36ab^{2}x}{(ax^{2} + bx + c)^{4}} + \frac{12ab}{(ax^{2} + bx + c)^{3}} - \frac{6b^{3}}{(ax^{2} + bx + c)^{4}}\right)}{dx}\\=&-48(\frac{-4(a*2x + b + 0)}{(ax^{2} + bx + c)^{5}})a^{3}x^{3} - \frac{48a^{3}*3x^{2}}{(ax^{2} + bx + c)^{4}} - 72(\frac{-4(a*2x + b + 0)}{(ax^{2} + bx + c)^{5}})a^{2}bx^{2} - \frac{72a^{2}b*2x}{(ax^{2} + bx + c)^{4}} + 24(\frac{-3(a*2x + b + 0)}{(ax^{2} + bx + c)^{4}})a^{2}x + \frac{24a^{2}}{(ax^{2} + bx + c)^{3}} - 36(\frac{-4(a*2x + b + 0)}{(ax^{2} + bx + c)^{5}})ab^{2}x - \frac{36ab^{2}}{(ax^{2} + bx + c)^{4}} + 12(\frac{-3(a*2x + b + 0)}{(ax^{2} + bx + c)^{4}})ab + 0 - 6(\frac{-4(a*2x + b + 0)}{(ax^{2} + bx + c)^{5}})b^{3} + 0\\=&\frac{384a^{4}x^{4}}{(ax^{2} + bx + c)^{5}} + \frac{768a^{3}bx^{3}}{(ax^{2} + bx + c)^{5}} - \frac{288a^{3}x^{2}}{(ax^{2} + bx + c)^{4}} + \frac{576a^{2}b^{2}x^{2}}{(ax^{2} + bx + c)^{5}} - \frac{288a^{2}bx}{(ax^{2} + bx + c)^{4}} + \frac{192ab^{3}x}{(ax^{2} + bx + c)^{5}} - \frac{72ab^{2}}{(ax^{2} + bx + c)^{4}} + \frac{24a^{2}}{(ax^{2} + bx + c)^{3}} + \frac{24b^{4}}{(ax^{2} + bx + c)^{5}}\\ \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!