3.1692 \(\int \sqrt{a+\frac{b}{x}} x^2 \, dx\)

Optimal. Leaf size=93 \[ -\frac{b^2 x \sqrt{a+\frac{b}{x}}}{8 a^2}+\frac{b^3 \tanh ^{-1}\left (\frac{\sqrt{a+\frac{b}{x}}}{\sqrt{a}}\right )}{8 a^{5/2}}+\frac{b x^2 \sqrt{a+\frac{b}{x}}}{12 a}+\frac{1}{3} x^3 \sqrt{a+\frac{b}{x}} \]

[Out]

-(b^2*Sqrt[a + b/x]*x)/(8*a^2) + (b*Sqrt[a + b/x]*x^2)/(12*a) + (Sqrt[a + b/x]*x^3)/3 + (b^3*ArcTanh[Sqrt[a +
b/x]/Sqrt[a]])/(8*a^(5/2))

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Rubi [A]  time = 0.0393377, antiderivative size = 93, normalized size of antiderivative = 1., number of steps used = 6, number of rules used = 5, integrand size = 15, \(\frac{\text{number of rules}}{\text{integrand size}}\) = 0.333, Rules used = {266, 47, 51, 63, 208} \[ -\frac{b^2 x \sqrt{a+\frac{b}{x}}}{8 a^2}+\frac{b^3 \tanh ^{-1}\left (\frac{\sqrt{a+\frac{b}{x}}}{\sqrt{a}}\right )}{8 a^{5/2}}+\frac{b x^2 \sqrt{a+\frac{b}{x}}}{12 a}+\frac{1}{3} x^3 \sqrt{a+\frac{b}{x}} \]

Antiderivative was successfully verified.

[In]

Int[Sqrt[a + b/x]*x^2,x]

[Out]

-(b^2*Sqrt[a + b/x]*x)/(8*a^2) + (b*Sqrt[a + b/x]*x^2)/(12*a) + (Sqrt[a + b/x]*x^3)/3 + (b^3*ArcTanh[Sqrt[a +
b/x]/Sqrt[a]])/(8*a^(5/2))

Rule 266

Int[(x_)^(m_.)*((a_) + (b_.)*(x_)^(n_))^(p_), x_Symbol] :> Dist[1/n, Subst[Int[x^(Simplify[(m + 1)/n] - 1)*(a
+ b*x)^p, x], x, x^n], x] /; FreeQ[{a, b, m, n, p}, x] && IntegerQ[Simplify[(m + 1)/n]]

Rule 47

Int[((a_.) + (b_.)*(x_))^(m_)*((c_.) + (d_.)*(x_))^(n_), x_Symbol] :> Simp[((a + b*x)^(m + 1)*(c + d*x)^n)/(b*
(m + 1)), x] - Dist[(d*n)/(b*(m + 1)), Int[(a + b*x)^(m + 1)*(c + d*x)^(n - 1), x], x] /; FreeQ[{a, b, c, d},
x] && NeQ[b*c - a*d, 0] && GtQ[n, 0] && LtQ[m, -1] &&  !(IntegerQ[n] &&  !IntegerQ[m]) &&  !(ILeQ[m + n + 2, 0
] && (FractionQ[m] || GeQ[2*n + m + 1, 0])) && IntLinearQ[a, b, c, d, m, n, x]

Rule 51

Int[((a_.) + (b_.)*(x_))^(m_)*((c_.) + (d_.)*(x_))^(n_), x_Symbol] :> Simp[((a + b*x)^(m + 1)*(c + d*x)^(n + 1
))/((b*c - a*d)*(m + 1)), x] - Dist[(d*(m + n + 2))/((b*c - a*d)*(m + 1)), Int[(a + b*x)^(m + 1)*(c + d*x)^n,
x], x] /; FreeQ[{a, b, c, d, n}, x] && NeQ[b*c - a*d, 0] && LtQ[m, -1] &&  !(LtQ[n, -1] && (EqQ[a, 0] || (NeQ[
c, 0] && LtQ[m - n, 0] && IntegerQ[n]))) && IntLinearQ[a, b, c, d, m, n, x]

Rule 63

Int[((a_.) + (b_.)*(x_))^(m_)*((c_.) + (d_.)*(x_))^(n_), x_Symbol] :> With[{p = Denominator[m]}, Dist[p/b, Sub
st[Int[x^(p*(m + 1) - 1)*(c - (a*d)/b + (d*x^p)/b)^n, x], x, (a + b*x)^(1/p)], x]] /; FreeQ[{a, b, c, d}, x] &
& NeQ[b*c - a*d, 0] && LtQ[-1, m, 0] && LeQ[-1, n, 0] && LeQ[Denominator[n], Denominator[m]] && IntLinearQ[a,
b, c, d, m, n, x]

Rule 208

Int[((a_) + (b_.)*(x_)^2)^(-1), x_Symbol] :> Simp[(Rt[-(a/b), 2]*ArcTanh[x/Rt[-(a/b), 2]])/a, x] /; FreeQ[{a,
b}, x] && NegQ[a/b]

Rubi steps

\begin{align*} \int \sqrt{a+\frac{b}{x}} x^2 \, dx &=-\operatorname{Subst}\left (\int \frac{\sqrt{a+b x}}{x^4} \, dx,x,\frac{1}{x}\right )\\ &=\frac{1}{3} \sqrt{a+\frac{b}{x}} x^3-\frac{1}{6} b \operatorname{Subst}\left (\int \frac{1}{x^3 \sqrt{a+b x}} \, dx,x,\frac{1}{x}\right )\\ &=\frac{b \sqrt{a+\frac{b}{x}} x^2}{12 a}+\frac{1}{3} \sqrt{a+\frac{b}{x}} x^3+\frac{b^2 \operatorname{Subst}\left (\int \frac{1}{x^2 \sqrt{a+b x}} \, dx,x,\frac{1}{x}\right )}{8 a}\\ &=-\frac{b^2 \sqrt{a+\frac{b}{x}} x}{8 a^2}+\frac{b \sqrt{a+\frac{b}{x}} x^2}{12 a}+\frac{1}{3} \sqrt{a+\frac{b}{x}} x^3-\frac{b^3 \operatorname{Subst}\left (\int \frac{1}{x \sqrt{a+b x}} \, dx,x,\frac{1}{x}\right )}{16 a^2}\\ &=-\frac{b^2 \sqrt{a+\frac{b}{x}} x}{8 a^2}+\frac{b \sqrt{a+\frac{b}{x}} x^2}{12 a}+\frac{1}{3} \sqrt{a+\frac{b}{x}} x^3-\frac{b^2 \operatorname{Subst}\left (\int \frac{1}{-\frac{a}{b}+\frac{x^2}{b}} \, dx,x,\sqrt{a+\frac{b}{x}}\right )}{8 a^2}\\ &=-\frac{b^2 \sqrt{a+\frac{b}{x}} x}{8 a^2}+\frac{b \sqrt{a+\frac{b}{x}} x^2}{12 a}+\frac{1}{3} \sqrt{a+\frac{b}{x}} x^3+\frac{b^3 \tanh ^{-1}\left (\frac{\sqrt{a+\frac{b}{x}}}{\sqrt{a}}\right )}{8 a^{5/2}}\\ \end{align*}

Mathematica [C]  time = 0.011731, size = 39, normalized size = 0.42 \[ -\frac{2 b^3 \left (a+\frac{b}{x}\right )^{3/2} \, _2F_1\left (\frac{3}{2},4;\frac{5}{2};\frac{b}{a x}+1\right )}{3 a^4} \]

Antiderivative was successfully verified.

[In]

Integrate[Sqrt[a + b/x]*x^2,x]

[Out]

(-2*b^3*(a + b/x)^(3/2)*Hypergeometric2F1[3/2, 4, 5/2, 1 + b/(a*x)])/(3*a^4)

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Maple [A]  time = 0.007, size = 115, normalized size = 1.2 \begin{align*}{\frac{x}{48}\sqrt{{\frac{ax+b}{x}}} \left ( 16\, \left ( a{x}^{2}+bx \right ) ^{3/2}{a}^{5/2}-12\,\sqrt{a{x}^{2}+bx}{a}^{5/2}xb-6\,\sqrt{a{x}^{2}+bx}{a}^{3/2}{b}^{2}+3\,\ln \left ( 1/2\,{\frac{2\,\sqrt{a{x}^{2}+bx}\sqrt{a}+2\,ax+b}{\sqrt{a}}} \right ) a{b}^{3} \right ){\frac{1}{\sqrt{ \left ( ax+b \right ) x}}}{a}^{-{\frac{7}{2}}}} \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

int(x^2*(a+b/x)^(1/2),x)

[Out]

1/48*((a*x+b)/x)^(1/2)*x*(16*(a*x^2+b*x)^(3/2)*a^(5/2)-12*(a*x^2+b*x)^(1/2)*a^(5/2)*x*b-6*(a*x^2+b*x)^(1/2)*a^
(3/2)*b^2+3*ln(1/2*(2*(a*x^2+b*x)^(1/2)*a^(1/2)+2*a*x+b)/a^(1/2))*a*b^3)/((a*x+b)*x)^(1/2)/a^(7/2)

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Maxima [F(-2)]  time = 0., size = 0, normalized size = 0. \begin{align*} \text{Exception raised: ValueError} \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(x^2*(a+b/x)^(1/2),x, algorithm="maxima")

[Out]

Exception raised: ValueError

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Fricas [A]  time = 1.76973, size = 351, normalized size = 3.77 \begin{align*} \left [\frac{3 \, \sqrt{a} b^{3} \log \left (2 \, a x + 2 \, \sqrt{a} x \sqrt{\frac{a x + b}{x}} + b\right ) + 2 \,{\left (8 \, a^{3} x^{3} + 2 \, a^{2} b x^{2} - 3 \, a b^{2} x\right )} \sqrt{\frac{a x + b}{x}}}{48 \, a^{3}}, -\frac{3 \, \sqrt{-a} b^{3} \arctan \left (\frac{\sqrt{-a} \sqrt{\frac{a x + b}{x}}}{a}\right ) -{\left (8 \, a^{3} x^{3} + 2 \, a^{2} b x^{2} - 3 \, a b^{2} x\right )} \sqrt{\frac{a x + b}{x}}}{24 \, a^{3}}\right ] \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(x^2*(a+b/x)^(1/2),x, algorithm="fricas")

[Out]

[1/48*(3*sqrt(a)*b^3*log(2*a*x + 2*sqrt(a)*x*sqrt((a*x + b)/x) + b) + 2*(8*a^3*x^3 + 2*a^2*b*x^2 - 3*a*b^2*x)*
sqrt((a*x + b)/x))/a^3, -1/24*(3*sqrt(-a)*b^3*arctan(sqrt(-a)*sqrt((a*x + b)/x)/a) - (8*a^3*x^3 + 2*a^2*b*x^2
- 3*a*b^2*x)*sqrt((a*x + b)/x))/a^3]

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Sympy [A]  time = 7.32848, size = 122, normalized size = 1.31 \begin{align*} \frac{a x^{\frac{7}{2}}}{3 \sqrt{b} \sqrt{\frac{a x}{b} + 1}} + \frac{5 \sqrt{b} x^{\frac{5}{2}}}{12 \sqrt{\frac{a x}{b} + 1}} - \frac{b^{\frac{3}{2}} x^{\frac{3}{2}}}{24 a \sqrt{\frac{a x}{b} + 1}} - \frac{b^{\frac{5}{2}} \sqrt{x}}{8 a^{2} \sqrt{\frac{a x}{b} + 1}} + \frac{b^{3} \operatorname{asinh}{\left (\frac{\sqrt{a} \sqrt{x}}{\sqrt{b}} \right )}}{8 a^{\frac{5}{2}}} \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(x**2*(a+b/x)**(1/2),x)

[Out]

a*x**(7/2)/(3*sqrt(b)*sqrt(a*x/b + 1)) + 5*sqrt(b)*x**(5/2)/(12*sqrt(a*x/b + 1)) - b**(3/2)*x**(3/2)/(24*a*sqr
t(a*x/b + 1)) - b**(5/2)*sqrt(x)/(8*a**2*sqrt(a*x/b + 1)) + b**3*asinh(sqrt(a)*sqrt(x)/sqrt(b))/(8*a**(5/2))

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Giac [A]  time = 1.17739, size = 127, normalized size = 1.37 \begin{align*} -\frac{b^{3} \log \left ({\left | -2 \,{\left (\sqrt{a} x - \sqrt{a x^{2} + b x}\right )} \sqrt{a} - b \right |}\right ) \mathrm{sgn}\left (x\right )}{16 \, a^{\frac{5}{2}}} + \frac{b^{3} \log \left ({\left | b \right |}\right ) \mathrm{sgn}\left (x\right )}{16 \, a^{\frac{5}{2}}} + \frac{1}{24} \, \sqrt{a x^{2} + b x}{\left (2 \,{\left (4 \, x \mathrm{sgn}\left (x\right ) + \frac{b \mathrm{sgn}\left (x\right )}{a}\right )} x - \frac{3 \, b^{2} \mathrm{sgn}\left (x\right )}{a^{2}}\right )} \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(x^2*(a+b/x)^(1/2),x, algorithm="giac")

[Out]

-1/16*b^3*log(abs(-2*(sqrt(a)*x - sqrt(a*x^2 + b*x))*sqrt(a) - b))*sgn(x)/a^(5/2) + 1/16*b^3*log(abs(b))*sgn(x
)/a^(5/2) + 1/24*sqrt(a*x^2 + b*x)*(2*(4*x*sgn(x) + b*sgn(x)/a)*x - 3*b^2*sgn(x)/a^2)