Optimal. Leaf size=108 \[ \frac {1}{3} \sqrt {\pi } b^3 \text {erf}(b x)^2+\frac {2 b^2 e^{-b^2 x^2} \text {erf}(b x)}{3 x}-\frac {e^{-b^2 x^2} \text {erf}(b x)}{3 x^3}-\frac {b e^{-2 b^2 x^2}}{3 \sqrt {\pi } x^2}-\frac {4 b^3 \text {Ei}\left (-2 b^2 x^2\right )}{3 \sqrt {\pi }} \]
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Rubi [A] time = 0.15, antiderivative size = 108, normalized size of antiderivative = 1.00, number of steps used = 7, number of rules used = 5, integrand size = 18, \(\frac {\text {number of rules}}{\text {integrand size}}\) = 0.278, Rules used = {6391, 6373, 30, 2210, 2214} \[ \frac {2 b^2 e^{-b^2 x^2} \text {Erf}(b x)}{3 x}-\frac {e^{-b^2 x^2} \text {Erf}(b x)}{3 x^3}+\frac {1}{3} \sqrt {\pi } b^3 \text {Erf}(b x)^2-\frac {4 b^3 \text {Ei}\left (-2 b^2 x^2\right )}{3 \sqrt {\pi }}-\frac {b e^{-2 b^2 x^2}}{3 \sqrt {\pi } x^2} \]
Antiderivative was successfully verified.
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Rule 30
Rule 2210
Rule 2214
Rule 6373
Rule 6391
Rubi steps
\begin {align*} \int \frac {e^{-b^2 x^2} \text {erf}(b x)}{x^4} \, dx &=-\frac {e^{-b^2 x^2} \text {erf}(b x)}{3 x^3}-\frac {1}{3} \left (2 b^2\right ) \int \frac {e^{-b^2 x^2} \text {erf}(b x)}{x^2} \, dx+\frac {(2 b) \int \frac {e^{-2 b^2 x^2}}{x^3} \, dx}{3 \sqrt {\pi }}\\ &=-\frac {b e^{-2 b^2 x^2}}{3 \sqrt {\pi } x^2}-\frac {e^{-b^2 x^2} \text {erf}(b x)}{3 x^3}+\frac {2 b^2 e^{-b^2 x^2} \text {erf}(b x)}{3 x}+\frac {1}{3} \left (4 b^4\right ) \int e^{-b^2 x^2} \text {erf}(b x) \, dx-2 \frac {\left (4 b^3\right ) \int \frac {e^{-2 b^2 x^2}}{x} \, dx}{3 \sqrt {\pi }}\\ &=-\frac {b e^{-2 b^2 x^2}}{3 \sqrt {\pi } x^2}-\frac {e^{-b^2 x^2} \text {erf}(b x)}{3 x^3}+\frac {2 b^2 e^{-b^2 x^2} \text {erf}(b x)}{3 x}-\frac {4 b^3 \text {Ei}\left (-2 b^2 x^2\right )}{3 \sqrt {\pi }}+\frac {1}{3} \left (2 b^3 \sqrt {\pi }\right ) \operatorname {Subst}(\int x \, dx,x,\text {erf}(b x))\\ &=-\frac {b e^{-2 b^2 x^2}}{3 \sqrt {\pi } x^2}-\frac {e^{-b^2 x^2} \text {erf}(b x)}{3 x^3}+\frac {2 b^2 e^{-b^2 x^2} \text {erf}(b x)}{3 x}+\frac {1}{3} b^3 \sqrt {\pi } \text {erf}(b x)^2-\frac {4 b^3 \text {Ei}\left (-2 b^2 x^2\right )}{3 \sqrt {\pi }}\\ \end {align*}
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Mathematica [A] time = 0.07, size = 85, normalized size = 0.79 \[ \frac {1}{3} \left (\sqrt {\pi } b^3 \text {erf}(b x)^2+\frac {e^{-b^2 x^2} \left (2 b^2 x^2-1\right ) \text {erf}(b x)}{x^3}+\frac {b \left (-4 b^2 \text {Ei}\left (-2 b^2 x^2\right )-\frac {e^{-2 b^2 x^2}}{x^2}\right )}{\sqrt {\pi }}\right ) \]
Antiderivative was successfully verified.
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fricas [A] time = 0.49, size = 84, normalized size = 0.78 \[ -\frac {{\left (\pi - 2 \, \pi b^{2} x^{2}\right )} \operatorname {erf}\left (b x\right ) e^{\left (-b^{2} x^{2}\right )} - \sqrt {\pi } {\left (\pi b^{3} x^{3} \operatorname {erf}\left (b x\right )^{2} - 4 \, b^{3} x^{3} {\rm Ei}\left (-2 \, b^{2} x^{2}\right ) - b x e^{\left (-2 \, b^{2} x^{2}\right )}\right )}}{3 \, \pi x^{3}} \]
Verification of antiderivative is not currently implemented for this CAS.
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giac [F] time = 0.00, size = 0, normalized size = 0.00 \[ \int \frac {\operatorname {erf}\left (b x\right ) e^{\left (-b^{2} x^{2}\right )}}{x^{4}}\,{d x} \]
Verification of antiderivative is not currently implemented for this CAS.
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maple [F] time = 0.24, size = 0, normalized size = 0.00 \[ \int \frac {\erf \left (b x \right ) {\mathrm e}^{-b^{2} x^{2}}}{x^{4}}\, dx \]
Verification of antiderivative is not currently implemented for this CAS.
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maxima [F] time = 0.00, size = 0, normalized size = 0.00 \[ \int \frac {\operatorname {erf}\left (b x\right ) e^{\left (-b^{2} x^{2}\right )}}{x^{4}}\,{d x} \]
Verification of antiderivative is not currently implemented for this CAS.
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mupad [F] time = 0.00, size = -1, normalized size = -0.01 \[ \int \frac {{\mathrm {e}}^{-b^2\,x^2}\,\mathrm {erf}\left (b\,x\right )}{x^4} \,d x \]
Verification of antiderivative is not currently implemented for this CAS.
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sympy [F] time = 0.00, size = 0, normalized size = 0.00 \[ \int \frac {e^{- b^{2} x^{2}} \operatorname {erf}{\left (b x \right )}}{x^{4}}\, dx \]
Verification of antiderivative is not currently implemented for this CAS.
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