Integrand size = 8, antiderivative size = 109 \[ \int x^6 \text {erfc}(b x) \, dx=-\frac {6 e^{-b^2 x^2}}{7 b^7 \sqrt {\pi }}-\frac {6 e^{-b^2 x^2} x^2}{7 b^5 \sqrt {\pi }}-\frac {3 e^{-b^2 x^2} x^4}{7 b^3 \sqrt {\pi }}-\frac {e^{-b^2 x^2} x^6}{7 b \sqrt {\pi }}+\frac {1}{7} x^7 \text {erfc}(b x) \]
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Time = 0.08 (sec) , antiderivative size = 109, normalized size of antiderivative = 1.00, number of steps used = 5, number of rules used = 3, \(\frac {\text {number of rules}}{\text {integrand size}}\) = 0.375, Rules used = {6497, 2243, 2240} \[ \int x^6 \text {erfc}(b x) \, dx=-\frac {x^6 e^{-b^2 x^2}}{7 \sqrt {\pi } b}-\frac {6 e^{-b^2 x^2}}{7 \sqrt {\pi } b^7}-\frac {6 x^2 e^{-b^2 x^2}}{7 \sqrt {\pi } b^5}-\frac {3 x^4 e^{-b^2 x^2}}{7 \sqrt {\pi } b^3}+\frac {1}{7} x^7 \text {erfc}(b x) \]
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Rule 2240
Rule 2243
Rule 6497
Rubi steps \begin{align*} \text {integral}& = \frac {1}{7} x^7 \text {erfc}(b x)+\frac {(2 b) \int e^{-b^2 x^2} x^7 \, dx}{7 \sqrt {\pi }} \\ & = -\frac {e^{-b^2 x^2} x^6}{7 b \sqrt {\pi }}+\frac {1}{7} x^7 \text {erfc}(b x)+\frac {6 \int e^{-b^2 x^2} x^5 \, dx}{7 b \sqrt {\pi }} \\ & = -\frac {3 e^{-b^2 x^2} x^4}{7 b^3 \sqrt {\pi }}-\frac {e^{-b^2 x^2} x^6}{7 b \sqrt {\pi }}+\frac {1}{7} x^7 \text {erfc}(b x)+\frac {12 \int e^{-b^2 x^2} x^3 \, dx}{7 b^3 \sqrt {\pi }} \\ & = -\frac {6 e^{-b^2 x^2} x^2}{7 b^5 \sqrt {\pi }}-\frac {3 e^{-b^2 x^2} x^4}{7 b^3 \sqrt {\pi }}-\frac {e^{-b^2 x^2} x^6}{7 b \sqrt {\pi }}+\frac {1}{7} x^7 \text {erfc}(b x)+\frac {12 \int e^{-b^2 x^2} x \, dx}{7 b^5 \sqrt {\pi }} \\ & = -\frac {6 e^{-b^2 x^2}}{7 b^7 \sqrt {\pi }}-\frac {6 e^{-b^2 x^2} x^2}{7 b^5 \sqrt {\pi }}-\frac {3 e^{-b^2 x^2} x^4}{7 b^3 \sqrt {\pi }}-\frac {e^{-b^2 x^2} x^6}{7 b \sqrt {\pi }}+\frac {1}{7} x^7 \text {erfc}(b x) \\ \end{align*}
Time = 0.01 (sec) , antiderivative size = 73, normalized size of antiderivative = 0.67 \[ \int x^6 \text {erfc}(b x) \, dx=\frac {e^{-b^2 x^2} \left (-6-6 b^2 x^2-3 b^4 x^4-b^6 x^6+b^7 e^{b^2 x^2} \sqrt {\pi } x^7 \text {erfc}(b x)\right )}{7 b^7 \sqrt {\pi }} \]
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Time = 0.39 (sec) , antiderivative size = 86, normalized size of antiderivative = 0.79
method | result | size |
parallelrisch | \(\frac {\operatorname {erfc}\left (b x \right ) x^{7} b^{7} \sqrt {\pi }-{\mathrm e}^{-b^{2} x^{2}} x^{6} b^{6}-3 \,{\mathrm e}^{-b^{2} x^{2}} x^{4} b^{4}-6 x^{2} {\mathrm e}^{-b^{2} x^{2}} b^{2}-6 \,{\mathrm e}^{-b^{2} x^{2}}}{7 b^{7} \sqrt {\pi }}\) | \(86\) |
derivativedivides | \(\frac {\frac {b^{7} x^{7} \operatorname {erfc}\left (b x \right )}{7}+\frac {-\frac {{\mathrm e}^{-b^{2} x^{2}} x^{6} b^{6}}{7}-\frac {3 \,{\mathrm e}^{-b^{2} x^{2}} x^{4} b^{4}}{7}-\frac {6 x^{2} {\mathrm e}^{-b^{2} x^{2}} b^{2}}{7}-\frac {6 \,{\mathrm e}^{-b^{2} x^{2}}}{7}}{\sqrt {\pi }}}{b^{7}}\) | \(90\) |
default | \(\frac {\frac {b^{7} x^{7} \operatorname {erfc}\left (b x \right )}{7}+\frac {-\frac {{\mathrm e}^{-b^{2} x^{2}} x^{6} b^{6}}{7}-\frac {3 \,{\mathrm e}^{-b^{2} x^{2}} x^{4} b^{4}}{7}-\frac {6 x^{2} {\mathrm e}^{-b^{2} x^{2}} b^{2}}{7}-\frac {6 \,{\mathrm e}^{-b^{2} x^{2}}}{7}}{\sqrt {\pi }}}{b^{7}}\) | \(90\) |
parts | \(\frac {x^{7} \operatorname {erfc}\left (b x \right )}{7}+\frac {2 b \left (-\frac {x^{6} {\mathrm e}^{-b^{2} x^{2}}}{2 b^{2}}+\frac {-\frac {3 x^{4} {\mathrm e}^{-b^{2} x^{2}}}{2 b^{2}}+\frac {3 \left (-\frac {x^{2} {\mathrm e}^{-b^{2} x^{2}}}{b^{2}}-\frac {{\mathrm e}^{-b^{2} x^{2}}}{b^{4}}\right )}{b^{2}}}{b^{2}}\right )}{7 \sqrt {\pi }}\) | \(95\) |
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Time = 0.25 (sec) , antiderivative size = 68, normalized size of antiderivative = 0.62 \[ \int x^6 \text {erfc}(b x) \, dx=-\frac {\pi b^{7} x^{7} \operatorname {erf}\left (b x\right ) - \pi b^{7} x^{7} + \sqrt {\pi } {\left (b^{6} x^{6} + 3 \, b^{4} x^{4} + 6 \, b^{2} x^{2} + 6\right )} e^{\left (-b^{2} x^{2}\right )}}{7 \, \pi b^{7}} \]
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Time = 0.52 (sec) , antiderivative size = 102, normalized size of antiderivative = 0.94 \[ \int x^6 \text {erfc}(b x) \, dx=\begin {cases} \frac {x^{7} \operatorname {erfc}{\left (b x \right )}}{7} - \frac {x^{6} e^{- b^{2} x^{2}}}{7 \sqrt {\pi } b} - \frac {3 x^{4} e^{- b^{2} x^{2}}}{7 \sqrt {\pi } b^{3}} - \frac {6 x^{2} e^{- b^{2} x^{2}}}{7 \sqrt {\pi } b^{5}} - \frac {6 e^{- b^{2} x^{2}}}{7 \sqrt {\pi } b^{7}} & \text {for}\: b \neq 0 \\\frac {x^{7}}{7} & \text {otherwise} \end {cases} \]
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Time = 0.21 (sec) , antiderivative size = 52, normalized size of antiderivative = 0.48 \[ \int x^6 \text {erfc}(b x) \, dx=\frac {1}{7} \, x^{7} \operatorname {erfc}\left (b x\right ) - \frac {{\left (b^{6} x^{6} + 3 \, b^{4} x^{4} + 6 \, b^{2} x^{2} + 6\right )} e^{\left (-b^{2} x^{2}\right )}}{7 \, \sqrt {\pi } b^{7}} \]
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Time = 0.27 (sec) , antiderivative size = 57, normalized size of antiderivative = 0.52 \[ \int x^6 \text {erfc}(b x) \, dx=-\frac {1}{7} \, x^{7} \operatorname {erf}\left (b x\right ) + \frac {1}{7} \, x^{7} - \frac {{\left (b^{6} x^{6} + 3 \, b^{4} x^{4} + 6 \, b^{2} x^{2} + 6\right )} e^{\left (-b^{2} x^{2}\right )}}{7 \, \sqrt {\pi } b^{7}} \]
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Time = 4.98 (sec) , antiderivative size = 90, normalized size of antiderivative = 0.83 \[ \int x^6 \text {erfc}(b x) \, dx=\frac {x^7\,\mathrm {erfc}\left (b\,x\right )}{7}-\frac {\frac {6\,{\mathrm {e}}^{-b^2\,x^2}}{7\,\sqrt {\pi }}+\frac {6\,b^2\,x^2\,{\mathrm {e}}^{-b^2\,x^2}}{7\,\sqrt {\pi }}+\frac {3\,b^4\,x^4\,{\mathrm {e}}^{-b^2\,x^2}}{7\,\sqrt {\pi }}+\frac {b^6\,x^6\,{\mathrm {e}}^{-b^2\,x^2}}{7\,\sqrt {\pi }}}{b^7} \]
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