Integrand size = 8, antiderivative size = 84 \[ \int x^4 \text {erf}(b x) \, dx=\frac {2 e^{-b^2 x^2}}{5 b^5 \sqrt {\pi }}+\frac {2 e^{-b^2 x^2} x^2}{5 b^3 \sqrt {\pi }}+\frac {e^{-b^2 x^2} x^4}{5 b \sqrt {\pi }}+\frac {1}{5} x^5 \text {erf}(b x) \]
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Time = 0.08 (sec) , antiderivative size = 84, normalized size of antiderivative = 1.00, number of steps used = 4, number of rules used = 3, \(\frac {\text {number of rules}}{\text {integrand size}}\) = 0.375, Rules used = {6496, 2243, 2240} \[ \int x^4 \text {erf}(b x) \, dx=\frac {x^4 e^{-b^2 x^2}}{5 \sqrt {\pi } b}+\frac {2 e^{-b^2 x^2}}{5 \sqrt {\pi } b^5}+\frac {2 x^2 e^{-b^2 x^2}}{5 \sqrt {\pi } b^3}+\frac {1}{5} x^5 \text {erf}(b x) \]
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Rule 2240
Rule 2243
Rule 6496
Rubi steps \begin{align*} \text {integral}& = \frac {1}{5} x^5 \text {erf}(b x)-\frac {(2 b) \int e^{-b^2 x^2} x^5 \, dx}{5 \sqrt {\pi }} \\ & = \frac {e^{-b^2 x^2} x^4}{5 b \sqrt {\pi }}+\frac {1}{5} x^5 \text {erf}(b x)-\frac {4 \int e^{-b^2 x^2} x^3 \, dx}{5 b \sqrt {\pi }} \\ & = \frac {2 e^{-b^2 x^2} x^2}{5 b^3 \sqrt {\pi }}+\frac {e^{-b^2 x^2} x^4}{5 b \sqrt {\pi }}+\frac {1}{5} x^5 \text {erf}(b x)-\frac {4 \int e^{-b^2 x^2} x \, dx}{5 b^3 \sqrt {\pi }} \\ & = \frac {2 e^{-b^2 x^2}}{5 b^5 \sqrt {\pi }}+\frac {2 e^{-b^2 x^2} x^2}{5 b^3 \sqrt {\pi }}+\frac {e^{-b^2 x^2} x^4}{5 b \sqrt {\pi }}+\frac {1}{5} x^5 \text {erf}(b x) \\ \end{align*}
Time = 0.01 (sec) , antiderivative size = 66, normalized size of antiderivative = 0.79 \[ \int x^4 \text {erf}(b x) \, dx=e^{-b^2 x^2} \left (\frac {2}{5 b^5 \sqrt {\pi }}+\frac {2 x^2}{5 b^3 \sqrt {\pi }}+\frac {x^4}{5 b \sqrt {\pi }}\right )+\frac {1}{5} x^5 \text {erf}(b x) \]
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Time = 0.31 (sec) , antiderivative size = 55, normalized size of antiderivative = 0.65
method | result | size |
meijerg | \(\frac {-\frac {4}{5}+\frac {2 \left (3 b^{4} x^{4}+6 b^{2} x^{2}+6\right ) {\mathrm e}^{-b^{2} x^{2}}}{15}+\frac {2 b^{5} x^{5} \operatorname {erf}\left (b x \right ) \sqrt {\pi }}{5}}{2 b^{5} \sqrt {\pi }}\) | \(55\) |
parallelrisch | \(\frac {b^{5} x^{5} \operatorname {erf}\left (b x \right ) \sqrt {\pi }+{\mathrm e}^{-b^{2} x^{2}} x^{4} b^{4}+2 x^{2} {\mathrm e}^{-b^{2} x^{2}} b^{2}+2 \,{\mathrm e}^{-b^{2} x^{2}}}{5 b^{5} \sqrt {\pi }}\) | \(68\) |
derivativedivides | \(\frac {\frac {\operatorname {erf}\left (b x \right ) b^{5} x^{5}}{5}-\frac {2 \left (-\frac {{\mathrm e}^{-b^{2} x^{2}} x^{4} b^{4}}{2}-x^{2} {\mathrm e}^{-b^{2} x^{2}} b^{2}-{\mathrm e}^{-b^{2} x^{2}}\right )}{5 \sqrt {\pi }}}{b^{5}}\) | \(72\) |
default | \(\frac {\frac {\operatorname {erf}\left (b x \right ) b^{5} x^{5}}{5}-\frac {2 \left (-\frac {{\mathrm e}^{-b^{2} x^{2}} x^{4} b^{4}}{2}-x^{2} {\mathrm e}^{-b^{2} x^{2}} b^{2}-{\mathrm e}^{-b^{2} x^{2}}\right )}{5 \sqrt {\pi }}}{b^{5}}\) | \(72\) |
parts | \(\frac {x^{5} \operatorname {erf}\left (b x \right )}{5}-\frac {2 b \left (-\frac {x^{4} {\mathrm e}^{-b^{2} x^{2}}}{2 b^{2}}+\frac {-\frac {x^{2} {\mathrm e}^{-b^{2} x^{2}}}{b^{2}}-\frac {{\mathrm e}^{-b^{2} x^{2}}}{b^{4}}}{b^{2}}\right )}{5 \sqrt {\pi }}\) | \(72\) |
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Time = 0.26 (sec) , antiderivative size = 51, normalized size of antiderivative = 0.61 \[ \int x^4 \text {erf}(b x) \, dx=\frac {\pi b^{5} x^{5} \operatorname {erf}\left (b x\right ) + \sqrt {\pi } {\left (b^{4} x^{4} + 2 \, b^{2} x^{2} + 2\right )} e^{\left (-b^{2} x^{2}\right )}}{5 \, \pi b^{5}} \]
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Time = 0.30 (sec) , antiderivative size = 75, normalized size of antiderivative = 0.89 \[ \int x^4 \text {erf}(b x) \, dx=\begin {cases} \frac {x^{5} \operatorname {erf}{\left (b x \right )}}{5} + \frac {x^{4} e^{- b^{2} x^{2}}}{5 \sqrt {\pi } b} + \frac {2 x^{2} e^{- b^{2} x^{2}}}{5 \sqrt {\pi } b^{3}} + \frac {2 e^{- b^{2} x^{2}}}{5 \sqrt {\pi } b^{5}} & \text {for}\: b \neq 0 \\0 & \text {otherwise} \end {cases} \]
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Time = 0.22 (sec) , antiderivative size = 44, normalized size of antiderivative = 0.52 \[ \int x^4 \text {erf}(b x) \, dx=\frac {1}{5} \, x^{5} \operatorname {erf}\left (b x\right ) + \frac {{\left (b^{4} x^{4} + 2 \, b^{2} x^{2} + 2\right )} e^{\left (-b^{2} x^{2}\right )}}{5 \, \sqrt {\pi } b^{5}} \]
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Time = 0.26 (sec) , antiderivative size = 44, normalized size of antiderivative = 0.52 \[ \int x^4 \text {erf}(b x) \, dx=\frac {1}{5} \, x^{5} \operatorname {erf}\left (b x\right ) + \frac {{\left (b^{4} x^{4} + 2 \, b^{2} x^{2} + 2\right )} e^{\left (-b^{2} x^{2}\right )}}{5 \, \sqrt {\pi } b^{5}} \]
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Time = 5.16 (sec) , antiderivative size = 44, normalized size of antiderivative = 0.52 \[ \int x^4 \text {erf}(b x) \, dx=\frac {x^5\,\mathrm {erf}\left (b\,x\right )}{5}+\frac {{\mathrm {e}}^{-b^2\,x^2}\,\left (b^4\,x^4+2\,b^2\,x^2+2\right )}{5\,b^5\,\sqrt {\pi }} \]
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