3.545 \(\int \frac{x^3}{\sqrt{9-4 x^2}} \, dx\)

Optimal. Leaf size=31 \[ \frac{1}{48} \left (9-4 x^2\right )^{3/2}-\frac{9}{16} \sqrt{9-4 x^2} \]

[Out]

(-9*Sqrt[9 - 4*x^2])/16 + (9 - 4*x^2)^(3/2)/48

________________________________________________________________________________________

Rubi [A]  time = 0.0135806, antiderivative size = 31, normalized size of antiderivative = 1., number of steps used = 3, number of rules used = 2, integrand size = 15, \(\frac{\text{number of rules}}{\text{integrand size}}\) = 0.133, Rules used = {266, 43} \[ \frac{1}{48} \left (9-4 x^2\right )^{3/2}-\frac{9}{16} \sqrt{9-4 x^2} \]

Antiderivative was successfully verified.

[In]

Int[x^3/Sqrt[9 - 4*x^2],x]

[Out]

(-9*Sqrt[9 - 4*x^2])/16 + (9 - 4*x^2)^(3/2)/48

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 43

Int[((a_.) + (b_.)*(x_))^(m_.)*((c_.) + (d_.)*(x_))^(n_.), x_Symbol] :> Int[ExpandIntegrand[(a + b*x)^m*(c + d
*x)^n, x], x] /; FreeQ[{a, b, c, d, n}, x] && NeQ[b*c - a*d, 0] && IGtQ[m, 0] && ( !IntegerQ[n] || (EqQ[c, 0]
&& LeQ[7*m + 4*n + 4, 0]) || LtQ[9*m + 5*(n + 1), 0] || GtQ[m + n + 2, 0])

Rubi steps

\begin{align*} \int \frac{x^3}{\sqrt{9-4 x^2}} \, dx &=\frac{1}{2} \operatorname{Subst}\left (\int \frac{x}{\sqrt{9-4 x}} \, dx,x,x^2\right )\\ &=\frac{1}{2} \operatorname{Subst}\left (\int \left (\frac{9}{4 \sqrt{9-4 x}}-\frac{1}{4} \sqrt{9-4 x}\right ) \, dx,x,x^2\right )\\ &=-\frac{9}{16} \sqrt{9-4 x^2}+\frac{1}{48} \left (9-4 x^2\right )^{3/2}\\ \end{align*}

Mathematica [A]  time = 0.0058884, size = 22, normalized size = 0.71 \[ -\frac{1}{24} \sqrt{9-4 x^2} \left (2 x^2+9\right ) \]

Antiderivative was successfully verified.

[In]

Integrate[x^3/Sqrt[9 - 4*x^2],x]

[Out]

-(Sqrt[9 - 4*x^2]*(9 + 2*x^2))/24

________________________________________________________________________________________

Maple [A]  time = 0.003, size = 29, normalized size = 0.9 \begin{align*}{\frac{ \left ( -3+2\,x \right ) \left ( 3+2\,x \right ) \left ( 2\,{x}^{2}+9 \right ) }{24}{\frac{1}{\sqrt{-4\,{x}^{2}+9}}}} \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

int(x^3/(-4*x^2+9)^(1/2),x)

[Out]

1/24*(-3+2*x)*(3+2*x)*(2*x^2+9)/(-4*x^2+9)^(1/2)

________________________________________________________________________________________

Maxima [A]  time = 3.20442, size = 35, normalized size = 1.13 \begin{align*} -\frac{1}{12} \, \sqrt{-4 \, x^{2} + 9} x^{2} - \frac{3}{8} \, \sqrt{-4 \, x^{2} + 9} \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(x^3/(-4*x^2+9)^(1/2),x, algorithm="maxima")

[Out]

-1/12*sqrt(-4*x^2 + 9)*x^2 - 3/8*sqrt(-4*x^2 + 9)

________________________________________________________________________________________

Fricas [A]  time = 1.25076, size = 49, normalized size = 1.58 \begin{align*} -\frac{1}{24} \,{\left (2 \, x^{2} + 9\right )} \sqrt{-4 \, x^{2} + 9} \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(x^3/(-4*x^2+9)^(1/2),x, algorithm="fricas")

[Out]

-1/24*(2*x^2 + 9)*sqrt(-4*x^2 + 9)

________________________________________________________________________________________

Sympy [A]  time = 0.344189, size = 29, normalized size = 0.94 \begin{align*} - \frac{x^{2} \sqrt{9 - 4 x^{2}}}{12} - \frac{3 \sqrt{9 - 4 x^{2}}}{8} \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(x**3/(-4*x**2+9)**(1/2),x)

[Out]

-x**2*sqrt(9 - 4*x**2)/12 - 3*sqrt(9 - 4*x**2)/8

________________________________________________________________________________________

Giac [A]  time = 2.56902, size = 31, normalized size = 1. \begin{align*} \frac{1}{48} \,{\left (-4 \, x^{2} + 9\right )}^{\frac{3}{2}} - \frac{9}{16} \, \sqrt{-4 \, x^{2} + 9} \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(x^3/(-4*x^2+9)^(1/2),x, algorithm="giac")

[Out]

1/48*(-4*x^2 + 9)^(3/2) - 9/16*sqrt(-4*x^2 + 9)