3.841 \(\int \frac{x^8}{\sqrt{a-b x^4}} \, dx\)

Optimal. Leaf size=100 \[ \frac{5 a^{9/4} \sqrt{1-\frac{b x^4}{a}} \text{EllipticF}\left (\sin ^{-1}\left (\frac{\sqrt [4]{b} x}{\sqrt [4]{a}}\right ),-1\right )}{21 b^{9/4} \sqrt{a-b x^4}}-\frac{5 a x \sqrt{a-b x^4}}{21 b^2}-\frac{x^5 \sqrt{a-b x^4}}{7 b} \]

[Out]

(-5*a*x*Sqrt[a - b*x^4])/(21*b^2) - (x^5*Sqrt[a - b*x^4])/(7*b) + (5*a^(9/4)*Sqrt[1 - (b*x^4)/a]*EllipticF[Arc
Sin[(b^(1/4)*x)/a^(1/4)], -1])/(21*b^(9/4)*Sqrt[a - b*x^4])

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Rubi [A]  time = 0.0341451, antiderivative size = 100, normalized size of antiderivative = 1., number of steps used = 4, number of rules used = 3, integrand size = 16, \(\frac{\text{number of rules}}{\text{integrand size}}\) = 0.188, Rules used = {321, 224, 221} \[ \frac{5 a^{9/4} \sqrt{1-\frac{b x^4}{a}} F\left (\left .\sin ^{-1}\left (\frac{\sqrt [4]{b} x}{\sqrt [4]{a}}\right )\right |-1\right )}{21 b^{9/4} \sqrt{a-b x^4}}-\frac{5 a x \sqrt{a-b x^4}}{21 b^2}-\frac{x^5 \sqrt{a-b x^4}}{7 b} \]

Antiderivative was successfully verified.

[In]

Int[x^8/Sqrt[a - b*x^4],x]

[Out]

(-5*a*x*Sqrt[a - b*x^4])/(21*b^2) - (x^5*Sqrt[a - b*x^4])/(7*b) + (5*a^(9/4)*Sqrt[1 - (b*x^4)/a]*EllipticF[Arc
Sin[(b^(1/4)*x)/a^(1/4)], -1])/(21*b^(9/4)*Sqrt[a - b*x^4])

Rule 321

Int[((c_.)*(x_))^(m_)*((a_) + (b_.)*(x_)^(n_))^(p_), x_Symbol] :> Simp[(c^(n - 1)*(c*x)^(m - n + 1)*(a + b*x^n
)^(p + 1))/(b*(m + n*p + 1)), x] - Dist[(a*c^n*(m - n + 1))/(b*(m + n*p + 1)), Int[(c*x)^(m - n)*(a + b*x^n)^p
, x], x] /; FreeQ[{a, b, c, p}, x] && IGtQ[n, 0] && GtQ[m, n - 1] && NeQ[m + n*p + 1, 0] && IntBinomialQ[a, b,
c, n, m, p, x]

Rule 224

Int[1/Sqrt[(a_) + (b_.)*(x_)^4], x_Symbol] :> Dist[Sqrt[1 + (b*x^4)/a]/Sqrt[a + b*x^4], Int[1/Sqrt[1 + (b*x^4)
/a], x], x] /; FreeQ[{a, b}, x] && NegQ[b/a] &&  !GtQ[a, 0]

Rule 221

Int[1/Sqrt[(a_) + (b_.)*(x_)^4], x_Symbol] :> Simp[EllipticF[ArcSin[(Rt[-b, 4]*x)/Rt[a, 4]], -1]/(Rt[a, 4]*Rt[
-b, 4]), x] /; FreeQ[{a, b}, x] && NegQ[b/a] && GtQ[a, 0]

Rubi steps

\begin{align*} \int \frac{x^8}{\sqrt{a-b x^4}} \, dx &=-\frac{x^5 \sqrt{a-b x^4}}{7 b}+\frac{(5 a) \int \frac{x^4}{\sqrt{a-b x^4}} \, dx}{7 b}\\ &=-\frac{5 a x \sqrt{a-b x^4}}{21 b^2}-\frac{x^5 \sqrt{a-b x^4}}{7 b}+\frac{\left (5 a^2\right ) \int \frac{1}{\sqrt{a-b x^4}} \, dx}{21 b^2}\\ &=-\frac{5 a x \sqrt{a-b x^4}}{21 b^2}-\frac{x^5 \sqrt{a-b x^4}}{7 b}+\frac{\left (5 a^2 \sqrt{1-\frac{b x^4}{a}}\right ) \int \frac{1}{\sqrt{1-\frac{b x^4}{a}}} \, dx}{21 b^2 \sqrt{a-b x^4}}\\ &=-\frac{5 a x \sqrt{a-b x^4}}{21 b^2}-\frac{x^5 \sqrt{a-b x^4}}{7 b}+\frac{5 a^{9/4} \sqrt{1-\frac{b x^4}{a}} F\left (\left .\sin ^{-1}\left (\frac{\sqrt [4]{b} x}{\sqrt [4]{a}}\right )\right |-1\right )}{21 b^{9/4} \sqrt{a-b x^4}}\\ \end{align*}

Mathematica [C]  time = 0.019846, size = 80, normalized size = 0.8 \[ \frac{5 a^2 x \sqrt{1-\frac{b x^4}{a}} \, _2F_1\left (\frac{1}{4},\frac{1}{2};\frac{5}{4};\frac{b x^4}{a}\right )-5 a^2 x+2 a b x^5+3 b^2 x^9}{21 b^2 \sqrt{a-b x^4}} \]

Antiderivative was successfully verified.

[In]

Integrate[x^8/Sqrt[a - b*x^4],x]

[Out]

(-5*a^2*x + 2*a*b*x^5 + 3*b^2*x^9 + 5*a^2*x*Sqrt[1 - (b*x^4)/a]*Hypergeometric2F1[1/4, 1/2, 5/4, (b*x^4)/a])/(
21*b^2*Sqrt[a - b*x^4])

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Maple [A]  time = 0.02, size = 107, normalized size = 1.1 \begin{align*} -{\frac{{x}^{5}}{7\,b}\sqrt{-b{x}^{4}+a}}-{\frac{5\,ax}{21\,{b}^{2}}\sqrt{-b{x}^{4}+a}}+{\frac{5\,{a}^{2}}{21\,{b}^{2}}\sqrt{1-{{x}^{2}\sqrt{b}{\frac{1}{\sqrt{a}}}}}\sqrt{1+{{x}^{2}\sqrt{b}{\frac{1}{\sqrt{a}}}}}{\it EllipticF} \left ( x\sqrt{{\sqrt{b}{\frac{1}{\sqrt{a}}}}},i \right ){\frac{1}{\sqrt{{\sqrt{b}{\frac{1}{\sqrt{a}}}}}}}{\frac{1}{\sqrt{-b{x}^{4}+a}}}} \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

int(x^8/(-b*x^4+a)^(1/2),x)

[Out]

-1/7*x^5*(-b*x^4+a)^(1/2)/b-5/21*a*x*(-b*x^4+a)^(1/2)/b^2+5/21*a^2/b^2/(1/a^(1/2)*b^(1/2))^(1/2)*(1-x^2*b^(1/2
)/a^(1/2))^(1/2)*(1+x^2*b^(1/2)/a^(1/2))^(1/2)/(-b*x^4+a)^(1/2)*EllipticF(x*(1/a^(1/2)*b^(1/2))^(1/2),I)

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Maxima [F]  time = 0., size = 0, normalized size = 0. \begin{align*} \int \frac{x^{8}}{\sqrt{-b x^{4} + a}}\,{d x} \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(x^8/(-b*x^4+a)^(1/2),x, algorithm="maxima")

[Out]

integrate(x^8/sqrt(-b*x^4 + a), x)

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Fricas [F]  time = 0., size = 0, normalized size = 0. \begin{align*}{\rm integral}\left (-\frac{\sqrt{-b x^{4} + a} x^{8}}{b x^{4} - a}, x\right ) \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(x^8/(-b*x^4+a)^(1/2),x, algorithm="fricas")

[Out]

integral(-sqrt(-b*x^4 + a)*x^8/(b*x^4 - a), x)

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Sympy [A]  time = 1.33588, size = 39, normalized size = 0.39 \begin{align*} \frac{x^{9} \Gamma \left (\frac{9}{4}\right ){{}_{2}F_{1}\left (\begin{matrix} \frac{1}{2}, \frac{9}{4} \\ \frac{13}{4} \end{matrix}\middle |{\frac{b x^{4} e^{2 i \pi }}{a}} \right )}}{4 \sqrt{a} \Gamma \left (\frac{13}{4}\right )} \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(x**8/(-b*x**4+a)**(1/2),x)

[Out]

x**9*gamma(9/4)*hyper((1/2, 9/4), (13/4,), b*x**4*exp_polar(2*I*pi)/a)/(4*sqrt(a)*gamma(13/4))

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Giac [F]  time = 0., size = 0, normalized size = 0. \begin{align*} \int \frac{x^{8}}{\sqrt{-b x^{4} + a}}\,{d x} \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(x^8/(-b*x^4+a)^(1/2),x, algorithm="giac")

[Out]

integrate(x^8/sqrt(-b*x^4 + a), x)