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无理函数积分表

以下是部份無理函數的积分表.

目录

[编辑] 包括r = \sqrt{a^2+x^2}的积分

\int r \;dx = \frac{1}{2}\left(x r +a^2\,\ln\left(\frac{x+r}{a}\right)\right)
\int r^3 \;dx = \frac{1}{4}xr^3+\frac{1}{8}3a^2xr+\frac{3}{8}a^4\ln\left(\frac{x+r}{a}\right)
\int r^5 \; dx = \frac{1}{6}xr^5+\frac{5}{24}a^2xr^3+\frac{5}{16}a^4xr+\frac{5}{16}a^6\ln\left(\frac{x+r}{a}\right)
\int x r\;dx=\frac{r^3}{3}
\int x r^3\;dx=\frac{r^5}{5}
\int x r^{2n+1}\;dx=\frac{r^{2n+3}}{2n+3}
\int x^2 r\;dx= \frac{xr^3}{4\frac{a^2xr}{8}-\frac{a^4}{8}\ln\left(\frac{x+r}{a}\right)}-
\int x^2 r^3\;dx= \frac{xr^5}{6\frac{a^2xr^3}{24}-\frac{a^4xr}{16}-\frac{a^6}{16}\ln\left(\frac{x+r}{a}\right)}-
\int x^3 r \; dx = \frac{r^5}{5} - \frac{a^2 r^3}{3}
\int x^3 r^3 \; dx = \frac{r^7}{7\frac{a^2r^5}{5}}-
\int x^3 r^{2n+1} \; dx = \frac{r^{2n+5}}{2n+5} - \frac{a^3 r^{2n+3}}{2n+3}
\int x^4 r\;dx= \frac{x^3r^3}{6\frac{a^2xr^3}{8}+\frac{a^4xr}{16}+\frac{a^6}{16}\ln\left(\frac{x+r}{a}\right)}-
\int x^4 r^3\;dx= \frac{x^3r^5}{8\frac{a^2xr^5}{16}+\frac{a^4xr^3}{64}+\frac{3a^6xr}{128}+\frac{3a^8}{128}\ln\left(\frac{x+r}{a}\right)}-
\int x^5 r \; dx = \frac{r^7}{7} - \frac{2 a^2 r^5}{5} + \frac{a^4 r^3}{3}
\int x^5 r^3 \; dx = \frac{r^9}{9} - \frac{2 a^2 r^7}{7} + \frac{a^4 r^5}{5}
\int x^5 r^{2n+1} \; dx = \frac{r^{2n+7}}{2n+7} - \frac{2a^2r^{2n+5}}{2n+5}+\frac{a^4 r^{2n+3}}{2n+3}
\int\frac{r\;dx}{x} = r-a\ln\left|\frac{a+r}{x}\right| = r - a \sinh^{-1}\frac{a}{x}
\int\frac{r^3\;dx}{x} = \frac{r^3}{3}+a^2r-a^3\ln\left|\frac{a+r}{x}\right|
\int\frac{r^5\;dx}{x} = \frac{r^5}{5}+\frac{a^2r^3}{3}+a^4r-a^5\ln\left|\frac{a+r}{x}\right|
\int\frac{r^7\;dx}{x} = \frac{r^7}{7}+\frac{a^2r^5}{5}+\frac{a^4r^3}{3}+a^6r-a^7\ln\left|\frac{a+r}{x}\right|
\int\frac{dx}{r} = \sinh^{-1}\frac{x}{a} = \ln\left|x+r\right|
\int\frac{x\,dx}{r} = r
\int\frac{x^2\;dx}{r} = \frac{x}{2}r-\frac{a^2}{2}\,\sinh^{-1}\frac{x}{a} = \frac{x}{2}r-\frac{a^2}{2}\ln\left|x+r\right|
\int\frac{dx}{xr} = -\frac{1}{a}\,\sinh^{-1}\frac{a}{x} = -\frac{1}{a}\ln\left|\frac{a+r}{x}\right|

[编辑] 包括s = \sqrt{x^2-a^2}的积分

假設 (x2 > a2), (x2 < a2)請看下一節:

\int xs\;dx = \frac{1}{3}s^3
\int\frac{s\;dx}{x} = s - a\cos^{-1}\left|\frac{a}{x}\right|
\int\frac{dx}{s} = \int\frac{dx}{\sqrt{x^2-a^2}} =\ln\left|\frac{x+s}{a}\right|

注意在\ln\left|\frac{x+s}{a}\right| =\mathrm{sgn}(x)\cosh^{-1}\left|\frac{x}{a}\right| =\frac{1}{2}\ln\left(\frac{x+s}{x-s}\right), 里\cosh^{-1}\left|\frac{x}{a}\right|取正值.

\int\frac{x\;dx}{s} = s
\int\frac{x\;dx}{s^3} = -\frac{1}{s}
\int\frac{x\;dx}{s^5} = -\frac{1}{3s^3}
\int\frac{x\;dx}{s^7} = -\frac{1}{5s^5}
\int\frac{x\;dx}{s^{2n+1}} = -\frac{1}{(2n-1)s^{2n-1}}
\int\frac{x^{2m}\;dx}{s^{2n+1}} = -\frac{1}{2n-1}\frac{x^{2m-1}}{s^{2n-1}}+\frac{2m-1}{2n-1}\int\frac{x^{2m-2}\;dx}{s^{2n-1}}
\int\frac{x^2\;dx}{s} = \frac{xs}{2}+\frac{a^2}{2}\ln\left|\frac{x+s}{a}\right|
\int\frac{x^2\;dx}{s^3} = -\frac{x}{s}+\ln\left|\frac{x+s}{a}\right|
\int\frac{x^4\;dx}{s} = \frac{x^3s}{4}+\frac{3}{8}a^2xs+\frac{3}{8}a^4\ln\left|\frac{x+s}{a}\right|
\int\frac{x^4\;dx}{s^3} = \frac{xs}{2\frac{a^2x}{s}+\frac{3}{2}a^2\ln\left|\frac{x+s}{a}\right|}-
\int\frac{x^4\;dx}{s^5} = -\frac{x}{s\frac{1}{3}\frac{x^3}{s^3}+\ln\left|\frac{x+s}{a}\right|}-
\int\frac{x^{2m}\;dx}{s^{2n+1}} = (-1)^{n-m}\frac{1}{a^{2(n-m)}}\sum_{i=0}^{n-m-1}\frac{1}{2(m+i)+1}{n-m-1 \choose i}\frac{x^{2(m+i)+1}}{s^{2(m+i)+1}}\qquad\mbox{(}n>m\ge0\mbox{)}
\int\frac{dx}{s^3}=-\frac{1}{a^2}\frac{x}{s}
\int\frac{dx}{s^5}=\frac{1}{a^4}\left[\frac{x}{s\frac{1}{3}\frac{x^3}{s^3}\right]}-
\int\frac{dx}{s^7} =-\frac{1}{a^6}\left[\frac{x}{s\frac{2}{3}\frac{x^3}{s^3}+\frac{1}{5}\frac{x^5}{s^5}\right]}-
\int\frac{dx}{s^9} =\frac{1}{a^8}\left[\frac{x}{s\frac{3}{3}\frac{x^3}{s^3}+\frac{3}{5}\frac{x^5}{s^5}-\frac{1}{7}\frac{x^7}{s^7}\right]}-
\int\frac{x^2\;dx}{s^5}=-\frac{1}{a^2}\frac{x^3}{3s^3}
\int\frac{x^2\;dx}{s^7} = \frac{1}{a^4}\left[\frac{1}{3}\frac{x^3}{s^3\frac{1}{5}\frac{x^5}{s^5}\right]}-
\int\frac{x^2\;dx}{s^9} = -\frac{1}{a^6}\left[\frac{1}{3}\frac{x^3}{s^3\frac{2}{5}\frac{x^5}{s^5}+\frac{1}{7}\frac{x^7}{s^7}\right]}-

[编辑] 包括t = \sqrt{a^2-x^2}的积分

\int t \;dx = \frac{1}{2}\left(xt+a^2\sin^{-1}\frac{x}{a}\right) \qquad\mbox{(}|x|\leq|a|\mbox{)}
\int xt\;dx = -\frac{1}{3} t^3 \qquad\mbox{(}|x|\leq|a|\mbox{)}
\int\frac{t\;dx}{x} = t-a\ln\left|\frac{a+t}{x}\right| \qquad\mbox{(}|x|\leq|a|\mbox{)}
\int\frac{dx}{t} = \sin^{-1}\frac{x}{a} \qquad\mbox{(}|x|\leq|a|\mbox{)}
\int\frac{x^2\;dx}{t} = -\frac{x}{2}t+\frac{a^2}{2}\sin^{-1}\frac{x}{a} \qquad\mbox{(}|x|\leq|a|\mbox{)}
\int t\;dx = \frac{1}{2}\left(xt-\sgn x\,\cosh^{-1}\left|\frac{x}{a}\right|\right) \qquad\mbox{(}|x|\ge|a|\mbox{)}

[编辑] 包括R^{1/2} = \sqrt{ax^2+bx+c}的积分

\int\frac{dx}{\sqrt{ax^2+bx+c}} = \frac{1}{\sqrt{a}}\ln\left|2\sqrt{a R}+2ax+b\right| \qquad\qquad \mbox{(}a>0\mbox{)}
\int\frac{dx}{\sqrt{ax^2+bx+c}} = \frac{1}{\sqrt{a}}\,\sinh^{-1}\frac{2ax+b}{\sqrt{4ac-b^2}} \qquad\qquad \mbox{(}a>0\mbox{, }4ac-b^2>0\mbox{)}
\int\frac{dx}{\sqrt{ax^2+bx+c}} = \frac{1}{\sqrt{a}}\ln|2ax+b| \quad \mbox{(}a>0\mbox{, }4ac-b^2=0\mbox{)}
\int\frac{dx}{\sqrt{ax^2+bx+c}} = -\frac{1}{\sqrt{-a}}\arcsin\frac{2ax+b}{\sqrt{b^2-4ac}} \qquad\qquad \mbox{(}a<0\mbox{, }4ac-b^2<0\mbox{)}
\int\frac{dx}{\sqrt{(ax^2+bx+c)^{3}}} = \frac{4ax+2b}{(4ac-b^2)\sqrt{R}}
\int\frac{dx}{\sqrt{(ax^2+bx+c)^{5}}} = \frac{4ax+2b}{3(4ac-b^2)\sqrt{R}}\left(\frac{1}{R}+\frac{8a}{4ac-b^2}\right)
\int\frac{dx}{\sqrt{(ax^2+bx+c)^{2n+1}}} = \frac{4ax+2b}{(2n-1)(4ac-b^2)R^{(2n-1)/2}}+\frac{8a(n-1)}{(2n-1)(4ac-b^2)} \int\frac{dx}{R^{(2n-1)/2}}
\int\frac{x\;dx}{\sqrt{ax^2+bx+c}} = \frac{\sqrt{R}}{a\frac{b}{2a}\int\frac{dx}{\sqrt{R}}}-
\int\frac{x\;dx}{\sqrt{(ax^2+bx+c)^3}} = -\frac{2bx+4c}{(4ac-b^2)\sqrt{R}}
\int\frac{x\;dx}{\sqrt{(ax^2+bx+c)^{2n+1}}} = -\frac{1}{(2n-1)aR^{(2n-1)/2}\frac{b}{2a}\int\frac{dx}{R^{(2n+1)/2}}}-
\int\frac{dx}{x\sqrt{ax^2+bx+c}}=-\frac{1}{\sqrt{c}}\ln\left(\frac{2\sqrt{c R}+bx+2c}{x}\right)
\int\frac{dx}{x\sqrt{ax^2+bx+c}}=-\frac{1}{\sqrt{c}}\sinh^{-1}\left(\frac{bx+2c}{|x|\sqrt{4ac-b^2}}\right)

[编辑] 包括R^{1/2} = \sqrt{ax+b}的积分

\int \frac{dx}{x\sqrt{ax + b}}\,=\,\frac{-2}{\sqrt{b}}\tanh^{-1}{\sqrt{\frac{ax + b}{b}}}
\int\frac{\sqrt{ax + b}}{x}\,dx\;=\;2\left(\sqrt{ax + b} - \sqrt{b}\tanh^{-1}{\sqrt{\frac{ax + b}{b}}}\right)
\int\frac{x^n}{\sqrt{ax + b}}\,dx\;=\;\frac{2}{a(2n+1)} \left(x^{n}\sqrt{ax + b} - bn\int\frac{x^{n-1}}{\sqrt{ax + b}}\right)
\int x^n \sqrt{ax + b}\,dx \; = \; \frac{2}{2n +1}\left(x^{n+1} \sqrt{ax + b} + bx^{n} \sqrt{ax + b} - nb\int x^{n-1}\sqrt{ax + b}\,dx \right)
来自“http://www.wikilib.com/wiki/%E6%97%A0%E7%90%86%E5%87%BD%E6%95%B0%E7%A7%AF%E5%88%86%E8%A1%A8”

1个分类: 积分表