Optimal. Leaf size=71 \[ \frac {3 \text {erf}(b x)}{16 b^4}-\frac {x^3 e^{-b^2 x^2}}{4 \sqrt {\pi } b}-\frac {3 x e^{-b^2 x^2}}{8 \sqrt {\pi } b^3}+\frac {1}{4} x^4 \text {erfc}(b x) \]
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Rubi [A] time = 0.06, antiderivative size = 71, normalized size of antiderivative = 1.00, number of steps used = 4, number of rules used = 3, integrand size = 8, \(\frac {\text {number of rules}}{\text {integrand size}}\) = 0.375, Rules used = {6362, 2212, 2205} \[ \frac {3 \text {Erf}(b x)}{16 b^4}-\frac {x^3 e^{-b^2 x^2}}{4 \sqrt {\pi } b}-\frac {3 x e^{-b^2 x^2}}{8 \sqrt {\pi } b^3}+\frac {1}{4} x^4 \text {Erfc}(b x) \]
Antiderivative was successfully verified.
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Rule 2205
Rule 2212
Rule 6362
Rubi steps
\begin {align*} \int x^3 \text {erfc}(b x) \, dx &=\frac {1}{4} x^4 \text {erfc}(b x)+\frac {b \int e^{-b^2 x^2} x^4 \, dx}{2 \sqrt {\pi }}\\ &=-\frac {e^{-b^2 x^2} x^3}{4 b \sqrt {\pi }}+\frac {1}{4} x^4 \text {erfc}(b x)+\frac {3 \int e^{-b^2 x^2} x^2 \, dx}{4 b \sqrt {\pi }}\\ &=-\frac {3 e^{-b^2 x^2} x}{8 b^3 \sqrt {\pi }}-\frac {e^{-b^2 x^2} x^3}{4 b \sqrt {\pi }}+\frac {1}{4} x^4 \text {erfc}(b x)+\frac {3 \int e^{-b^2 x^2} \, dx}{8 b^3 \sqrt {\pi }}\\ &=-\frac {3 e^{-b^2 x^2} x}{8 b^3 \sqrt {\pi }}-\frac {e^{-b^2 x^2} x^3}{4 b \sqrt {\pi }}+\frac {3 \text {erf}(b x)}{16 b^4}+\frac {1}{4} x^4 \text {erfc}(b x)\\ \end {align*}
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Mathematica [A] time = 0.06, size = 54, normalized size = 0.76 \[ \frac {1}{16} \left (\frac {3 \text {erf}(b x)}{b^4}-\frac {2 x e^{-b^2 x^2} \left (2 b^2 x^2+3\right )}{\sqrt {\pi } b^3}+4 x^4 \text {erfc}(b x)\right ) \]
Antiderivative was successfully verified.
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fricas [A] time = 0.47, size = 63, normalized size = 0.89 \[ \frac {4 \, \pi b^{4} x^{4} - 2 \, \sqrt {\pi } {\left (2 \, b^{3} x^{3} + 3 \, b x\right )} e^{\left (-b^{2} x^{2}\right )} + {\left (3 \, \pi - 4 \, \pi b^{4} x^{4}\right )} \operatorname {erf}\left (b x\right )}{16 \, \pi b^{4}} \]
Verification of antiderivative is not currently implemented for this CAS.
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giac [A] time = 0.38, size = 61, normalized size = 0.86 \[ -\frac {1}{4} \, x^{4} \operatorname {erf}\left (b x\right ) + \frac {1}{4} \, x^{4} - \frac {b {\left (\frac {2 \, {\left (2 \, b^{2} x^{3} + 3 \, x\right )} e^{\left (-b^{2} x^{2}\right )}}{b^{4}} + \frac {3 \, \sqrt {\pi } \operatorname {erf}\left (-b x\right )}{b^{5}}\right )}}{16 \, \sqrt {\pi }} \]
Verification of antiderivative is not currently implemented for this CAS.
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maple [A] time = 0.00, size = 65, normalized size = 0.92 \[ \frac {\frac {b^{4} x^{4} \mathrm {erfc}\left (b x \right )}{4}+\frac {-\frac {b^{3} x^{3} {\mathrm e}^{-b^{2} x^{2}}}{2}-\frac {3 \,{\mathrm e}^{-b^{2} x^{2}} b x}{4}+\frac {3 \sqrt {\pi }\, \erf \left (b x \right )}{8}}{2 \sqrt {\pi }}}{b^{4}} \]
Verification of antiderivative is not currently implemented for this CAS.
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maxima [A] time = 0.58, size = 55, normalized size = 0.77 \[ \frac {1}{4} \, x^{4} \operatorname {erfc}\left (b x\right ) - \frac {b {\left (\frac {2 \, {\left (2 \, b^{2} x^{3} + 3 \, x\right )} e^{\left (-b^{2} x^{2}\right )}}{b^{4}} - \frac {3 \, \sqrt {\pi } \operatorname {erf}\left (b x\right )}{b^{5}}\right )}}{16 \, \sqrt {\pi }} \]
Verification of antiderivative is not currently implemented for this CAS.
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mupad [B] time = 0.14, size = 58, normalized size = 0.82 \[ \frac {x^4\,\mathrm {erfc}\left (b\,x\right )}{4}-\frac {\frac {3\,\mathrm {erfc}\left (b\,x\right )}{16}+\frac {b^3\,x^3\,{\mathrm {e}}^{-b^2\,x^2}}{4\,\sqrt {\pi }}+\frac {3\,b\,x\,{\mathrm {e}}^{-b^2\,x^2}}{8\,\sqrt {\pi }}}{b^4} \]
Verification of antiderivative is not currently implemented for this CAS.
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sympy [A] time = 1.04, size = 68, normalized size = 0.96 \[ \begin {cases} \frac {x^{4} \operatorname {erfc}{\left (b x \right )}}{4} - \frac {x^{3} e^{- b^{2} x^{2}}}{4 \sqrt {\pi } b} - \frac {3 x e^{- b^{2} x^{2}}}{8 \sqrt {\pi } b^{3}} - \frac {3 \operatorname {erfc}{\left (b x \right )}}{16 b^{4}} & \text {for}\: b \neq 0 \\\frac {x^{4}}{4} & \text {otherwise} \end {cases} \]
Verification of antiderivative is not currently implemented for this CAS.
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