3.31 \(\int \text {erf}(b x)^2 \, dx\)

Optimal. Leaf size=56 \[ \frac {2 e^{-b^2 x^2} \text {erf}(b x)}{\sqrt {\pi } b}+x \text {erf}(b x)^2-\frac {\sqrt {\frac {2}{\pi }} \text {erf}\left (\sqrt {2} b x\right )}{b} \]

[Out]

x*erf(b*x)^2-erf(b*x*2^(1/2))*2^(1/2)/Pi^(1/2)/b+2*erf(b*x)/b/exp(b^2*x^2)/Pi^(1/2)

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Rubi [A]  time = 0.05, antiderivative size = 56, normalized size of antiderivative = 1.00, number of steps used = 4, number of rules used = 4, integrand size = 6, \(\frac {\text {number of rules}}{\text {integrand size}}\) = 0.667, Rules used = {6352, 12, 6382, 2205} \[ \frac {2 e^{-b^2 x^2} \text {Erf}(b x)}{\sqrt {\pi } b}+x \text {Erf}(b x)^2-\frac {\sqrt {\frac {2}{\pi }} \text {Erf}\left (\sqrt {2} b x\right )}{b} \]

Antiderivative was successfully verified.

[In]

Int[Erf[b*x]^2,x]

[Out]

(2*Erf[b*x])/(b*E^(b^2*x^2)*Sqrt[Pi]) + x*Erf[b*x]^2 - (Sqrt[2/Pi]*Erf[Sqrt[2]*b*x])/b

Rule 12

Int[(a_)*(u_), x_Symbol] :> Dist[a, Int[u, x], x] /; FreeQ[a, x] &&  !MatchQ[u, (b_)*(v_) /; FreeQ[b, x]]

Rule 2205

Int[(F_)^((a_.) + (b_.)*((c_.) + (d_.)*(x_))^2), x_Symbol] :> Simp[(F^a*Sqrt[Pi]*Erf[(c + d*x)*Rt[-(b*Log[F]),
2]])/(2*d*Rt[-(b*Log[F]), 2]), x] /; FreeQ[{F, a, b, c, d}, x] && NegQ[b]

Rule 6352

Int[Erf[(a_.) + (b_.)*(x_)]^2, x_Symbol] :> Simp[((a + b*x)*Erf[a + b*x]^2)/b, x] - Dist[4/Sqrt[Pi], Int[((a +
b*x)*Erf[a + b*x])/E^(a + b*x)^2, x], x] /; FreeQ[{a, b}, x]

Rule 6382

Int[E^((c_.) + (d_.)*(x_)^2)*Erf[(a_.) + (b_.)*(x_)]*(x_), x_Symbol] :> Simp[(E^(c + d*x^2)*Erf[a + b*x])/(2*d
), x] - Dist[b/(d*Sqrt[Pi]), Int[E^(-a^2 + c - 2*a*b*x - (b^2 - d)*x^2), x], x] /; FreeQ[{a, b, c, d}, x]

Rubi steps

\begin {align*} \int \text {erf}(b x)^2 \, dx &=x \text {erf}(b x)^2-\frac {4 \int b e^{-b^2 x^2} x \text {erf}(b x) \, dx}{\sqrt {\pi }}\\ &=x \text {erf}(b x)^2-\frac {(4 b) \int e^{-b^2 x^2} x \text {erf}(b x) \, dx}{\sqrt {\pi }}\\ &=\frac {2 e^{-b^2 x^2} \text {erf}(b x)}{b \sqrt {\pi }}+x \text {erf}(b x)^2-\frac {4 \int e^{-2 b^2 x^2} \, dx}{\pi }\\ &=\frac {2 e^{-b^2 x^2} \text {erf}(b x)}{b \sqrt {\pi }}+x \text {erf}(b x)^2-\frac {\sqrt {\frac {2}{\pi }} \text {erf}\left (\sqrt {2} b x\right )}{b}\\ \end {align*}

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Mathematica [A]  time = 0.03, size = 56, normalized size = 1.00 \[ \frac {2 e^{-b^2 x^2} \text {erf}(b x)}{\sqrt {\pi } b}+x \text {erf}(b x)^2-\frac {\sqrt {\frac {2}{\pi }} \text {erf}\left (\sqrt {2} b x\right )}{b} \]

Antiderivative was successfully verified.

[In]

Integrate[Erf[b*x]^2,x]

[Out]

(2*Erf[b*x])/(b*E^(b^2*x^2)*Sqrt[Pi]) + x*Erf[b*x]^2 - (Sqrt[2/Pi]*Erf[Sqrt[2]*b*x])/b

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fricas [A]  time = 0.82, size = 63, normalized size = 1.12 \[ \frac {\pi b^{2} x \operatorname {erf}\left (b x\right )^{2} + 2 \, \sqrt {\pi } b \operatorname {erf}\left (b x\right ) e^{\left (-b^{2} x^{2}\right )} - \sqrt {2} \sqrt {\pi } \sqrt {b^{2}} \operatorname {erf}\left (\sqrt {2} \sqrt {b^{2}} x\right )}{\pi b^{2}} \]

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(erf(b*x)^2,x, algorithm="fricas")

[Out]

(pi*b^2*x*erf(b*x)^2 + 2*sqrt(pi)*b*erf(b*x)*e^(-b^2*x^2) - sqrt(2)*sqrt(pi)*sqrt(b^2)*erf(sqrt(2)*sqrt(b^2)*x
))/(pi*b^2)

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giac [A]  time = 0.30, size = 48, normalized size = 0.86 \[ x \operatorname {erf}\left (b x\right )^{2} + \frac {b {\left (\frac {2 \, \operatorname {erf}\left (b x\right ) e^{\left (-b^{2} x^{2}\right )}}{b^{2}} + \frac {\sqrt {2} \operatorname {erf}\left (-\sqrt {2} b x\right )}{b^{2}}\right )}}{\sqrt {\pi }} \]

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(erf(b*x)^2,x, algorithm="giac")

[Out]

x*erf(b*x)^2 + b*(2*erf(b*x)*e^(-b^2*x^2)/b^2 + sqrt(2)*erf(-sqrt(2)*b*x)/b^2)/sqrt(pi)

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maple [A]  time = 0.01, size = 48, normalized size = 0.86 \[ \frac {b x \erf \left (b x \right )^{2}+\frac {2 \erf \left (b x \right ) {\mathrm e}^{-b^{2} x^{2}}}{\sqrt {\pi }}-\frac {\sqrt {2}\, \erf \left (b x \sqrt {2}\right )}{\sqrt {\pi }}}{b} \]

Verification of antiderivative is not currently implemented for this CAS.

[In]

int(erf(b*x)^2,x)

[Out]

1/b*(b*x*erf(b*x)^2+2*erf(b*x)/Pi^(1/2)*exp(-b^2*x^2)-1/Pi^(1/2)*2^(1/2)*erf(b*x*2^(1/2)))

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maxima [A]  time = 0.58, size = 62, normalized size = 1.11 \[ \frac {{\left (\sqrt {\pi } b x \operatorname {erf}\left (b x\right )^{2} e^{\left (b^{2} x^{2}\right )} + 2 \, \operatorname {erf}\left (b x\right )\right )} e^{\left (-b^{2} x^{2}\right )}}{\sqrt {\pi } b} - \frac {\sqrt {2} \operatorname {erf}\left (\sqrt {2} b x\right )}{\sqrt {\pi } b} \]

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(erf(b*x)^2,x, algorithm="maxima")

[Out]

(sqrt(pi)*b*x*erf(b*x)^2*e^(b^2*x^2) + 2*erf(b*x))*e^(-b^2*x^2)/(sqrt(pi)*b) - sqrt(2)*erf(sqrt(2)*b*x)/(sqrt(
pi)*b)

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mupad [B]  time = 0.16, size = 44, normalized size = 0.79 \[ x\,{\mathrm {erf}\left (b\,x\right )}^2+\frac {2\,{\mathrm {e}}^{-b^2\,x^2}\,\mathrm {erf}\left (b\,x\right )-\sqrt {2}\,\mathrm {erf}\left (\sqrt {2}\,b\,x\right )}{b\,\sqrt {\pi }} \]

Verification of antiderivative is not currently implemented for this CAS.

[In]

int(erf(b*x)^2,x)

[Out]

x*erf(b*x)^2 + (2*exp(-b^2*x^2)*erf(b*x) - 2^(1/2)*erf(2^(1/2)*b*x))/(b*pi^(1/2))

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sympy [F]  time = 0.00, size = 0, normalized size = 0.00 \[ \int \operatorname {erf}^{2}{\left (b x \right )}\, dx \]

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(erf(b*x)**2,x)

[Out]

Integral(erf(b*x)**2, x)

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