3.549 \(\int \frac {1}{x \sqrt {9-4 x^2}} \, dx\)

Optimal. Leaf size=20 \[ -\frac {1}{3} \tanh ^{-1}\left (\frac {1}{3} \sqrt {9-4 x^2}\right ) \]

[Out]

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

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Rubi [A]  time = 0.01, antiderivative size = 20, normalized size of antiderivative = 1.00, number of steps used = 3, number of rules used = 3, integrand size = 15, \(\frac {\text {number of rules}}{\text {integrand size}}\) = 0.200, Rules used = {266, 63, 206} \[ -\frac {1}{3} \tanh ^{-1}\left (\frac {1}{3} \sqrt {9-4 x^2}\right ) \]

Antiderivative was successfully verified.

[In]

Int[1/(x*Sqrt[9 - 4*x^2]),x]

[Out]

-ArcTanh[Sqrt[9 - 4*x^2]/3]/3

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 206

Int[((a_) + (b_.)*(x_)^2)^(-1), x_Symbol] :> Simp[(1*ArcTanh[(Rt[-b, 2]*x)/Rt[a, 2]])/(Rt[a, 2]*Rt[-b, 2]), x]
/; FreeQ[{a, b}, x] && NegQ[a/b] && (GtQ[a, 0] || LtQ[b, 0])

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]]

Rubi steps

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

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Mathematica [A]  time = 0.00, size = 20, normalized size = 1.00 \[ -\frac {1}{3} \tanh ^{-1}\left (\frac {1}{3} \sqrt {9-4 x^2}\right ) \]

Antiderivative was successfully verified.

[In]

Integrate[1/(x*Sqrt[9 - 4*x^2]),x]

[Out]

-1/3*ArcTanh[Sqrt[9 - 4*x^2]/3]

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fricas [A]  time = 0.57, size = 18, normalized size = 0.90 \[ \frac {1}{3} \, \log \left (\frac {\sqrt {-4 \, x^{2} + 9} - 3}{x}\right ) \]

Verification of antiderivative is not currently implemented for this CAS.

[In]

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

[Out]

1/3*log((sqrt(-4*x^2 + 9) - 3)/x)

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giac [B]  time = 0.94, size = 31, normalized size = 1.55 \[ -\frac {1}{6} \, \log \left (\sqrt {-4 \, x^{2} + 9} + 3\right ) + \frac {1}{6} \, \log \left (-\sqrt {-4 \, x^{2} + 9} + 3\right ) \]

Verification of antiderivative is not currently implemented for this CAS.

[In]

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

[Out]

-1/6*log(sqrt(-4*x^2 + 9) + 3) + 1/6*log(-sqrt(-4*x^2 + 9) + 3)

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maple [A]  time = 0.00, size = 15, normalized size = 0.75 \[ -\frac {\arctanh \left (\frac {3}{\sqrt {-4 x^{2}+9}}\right )}{3} \]

Verification of antiderivative is not currently implemented for this CAS.

[In]

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

[Out]

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

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maxima [A]  time = 2.99, size = 25, normalized size = 1.25 \[ -\frac {1}{3} \, \log \left (\frac {6 \, \sqrt {-4 \, x^{2} + 9}}{{\left | x \right |}} + \frac {18}{{\left | x \right |}}\right ) \]

Verification of antiderivative is not currently implemented for this CAS.

[In]

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

[Out]

-1/3*log(6*sqrt(-4*x^2 + 9)/abs(x) + 18/abs(x))

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mupad [B]  time = 0.12, size = 20, normalized size = 1.00 \[ \frac {\ln \left (\sqrt {\frac {9}{4\,x^2}-1}-\frac {3\,\sqrt {\frac {1}{x^2}}}{2}\right )}{3} \]

Verification of antiderivative is not currently implemented for this CAS.

[In]

int(1/(x*(9 - 4*x^2)^(1/2)),x)

[Out]

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

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sympy [A]  time = 1.06, size = 26, normalized size = 1.30 \[ \begin {cases} - \frac {\operatorname {acosh}{\left (\frac {3}{2 x} \right )}}{3} & \text {for}\: \frac {9}{4 \left |{x^{2}}\right |} > 1 \\\frac {i \operatorname {asin}{\left (\frac {3}{2 x} \right )}}{3} & \text {otherwise} \end {cases} \]

Verification of antiderivative is not currently implemented for this CAS.

[In]

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

[Out]

Piecewise((-acosh(3/(2*x))/3, 9/(4*Abs(x**2)) > 1), (I*asin(3/(2*x))/3, True))

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