3.1.54 \(\int \frac {1}{x^2 \sqrt {a x^2+b x^3+c x^4}} \, dx\)

Optimal. Leaf size=119 \[ -\frac {\left (3 b^2-4 a c\right ) \tanh ^{-1}\left (\frac {x (2 a+b x)}{2 \sqrt {a} \sqrt {a x^2+b x^3+c x^4}}\right )}{8 a^{5/2}}+\frac {3 b \sqrt {a x^2+b x^3+c x^4}}{4 a^2 x^2}-\frac {\sqrt {a x^2+b x^3+c x^4}}{2 a x^3} \]

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Rubi [A]  time = 0.15, antiderivative size = 119, normalized size of antiderivative = 1.00, number of steps used = 5, number of rules used = 5, integrand size = 24, \(\frac {\text {number of rules}}{\text {integrand size}}\) = 0.208, Rules used = {1929, 1951, 12, 1904, 206} \begin {gather*} -\frac {\left (3 b^2-4 a c\right ) \tanh ^{-1}\left (\frac {x (2 a+b x)}{2 \sqrt {a} \sqrt {a x^2+b x^3+c x^4}}\right )}{8 a^{5/2}}+\frac {3 b \sqrt {a x^2+b x^3+c x^4}}{4 a^2 x^2}-\frac {\sqrt {a x^2+b x^3+c x^4}}{2 a x^3} \end {gather*}

Antiderivative was successfully verified.

[In]

Int[1/(x^2*Sqrt[a*x^2 + b*x^3 + c*x^4]),x]

[Out]

-Sqrt[a*x^2 + b*x^3 + c*x^4]/(2*a*x^3) + (3*b*Sqrt[a*x^2 + b*x^3 + c*x^4])/(4*a^2*x^2) - ((3*b^2 - 4*a*c)*ArcT
anh[(x*(2*a + b*x))/(2*Sqrt[a]*Sqrt[a*x^2 + b*x^3 + c*x^4])])/(8*a^(5/2))

Rule 12

Int[(a_)*(u_), x_Symbol] :> Dist[a, Int[u, x], x] /; FreeQ[a, x] &&  !MatchQ[u, (b_)*(v_) /; FreeQ[b, 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 1904

Int[1/Sqrt[(a_.)*(x_)^2 + (b_.)*(x_)^(n_.) + (c_.)*(x_)^(r_.)], x_Symbol] :> Dist[-2/(n - 2), Subst[Int[1/(4*a
- x^2), x], x, (x*(2*a + b*x^(n - 2)))/Sqrt[a*x^2 + b*x^n + c*x^r]], x] /; FreeQ[{a, b, c, n, r}, x] && EqQ[r
, 2*n - 2] && PosQ[n - 2] && NeQ[b^2 - 4*a*c, 0]

Rule 1929

Int[(x_)^(m_.)*((b_.)*(x_)^(n_.) + (a_.)*(x_)^(q_.) + (c_.)*(x_)^(r_.))^(p_), x_Symbol] :> Simp[(x^(m - q + 1)
*(a*x^q + b*x^n + c*x^(2*n - q))^(p + 1))/(a*(m + p*q + 1)), x] - Dist[1/(a*(m + p*q + 1)), Int[x^(m + n - q)*
(b*(m + p*q + (n - q)*(p + 1) + 1) + c*(m + p*q + 2*(n - q)*(p + 1) + 1)*x^(n - q))*(a*x^q + b*x^n + c*x^(2*n
- q))^p, x], x] /; FreeQ[{a, b, c}, x] && EqQ[r, 2*n - q] && PosQ[n - q] &&  !IntegerQ[p] && NeQ[b^2 - 4*a*c,
0] && IGtQ[n, 0] && GeQ[p, -1] && LtQ[p, 0] && RationalQ[m, q] && LtQ[m + p*q + 1, 0]

Rule 1951

Int[(x_)^(m_.)*((c_.)*(x_)^(j_.) + (b_.)*(x_)^(n_.) + (a_.)*(x_)^(q_.))^(p_.)*((A_) + (B_.)*(x_)^(r_.)), x_Sym
bol] :> Simp[(A*x^(m - q + 1)*(a*x^q + b*x^n + c*x^(2*n - q))^(p + 1))/(a*(m + p*q + 1)), x] + Dist[1/(a*(m +
p*q + 1)), Int[x^(m + n - q)*Simp[a*B*(m + p*q + 1) - A*b*(m + p*q + (n - q)*(p + 1) + 1) - A*c*(m + p*q + 2*(
n - q)*(p + 1) + 1)*x^(n - q), x]*(a*x^q + b*x^n + c*x^(2*n - q))^p, x], x] /; FreeQ[{a, b, c, A, B}, x] && Eq
Q[r, n - q] && EqQ[j, 2*n - q] &&  !IntegerQ[p] && NeQ[b^2 - 4*a*c, 0] && IGtQ[n, 0] && RationalQ[m, p, q] &&
((GeQ[p, -1] && LtQ[p, 0]) || EqQ[m + p*q + (n - q)*(2*p + 1) + 1, 0]) && LeQ[m + p*q, -(n - q)] && NeQ[m + p*
q + 1, 0]

Rubi steps

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

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Mathematica [A]  time = 0.08, size = 112, normalized size = 0.94 \begin {gather*} \frac {-\left (x^2 \left (3 b^2-4 a c\right ) \sqrt {a+x (b+c x)} \tanh ^{-1}\left (\frac {2 a+b x}{2 \sqrt {a} \sqrt {a+x (b+c x)}}\right )\right )-2 \sqrt {a} (2 a-3 b x) (a+x (b+c x))}{8 a^{5/2} x \sqrt {x^2 (a+x (b+c x))}} \end {gather*}

Antiderivative was successfully verified.

[In]

Integrate[1/(x^2*Sqrt[a*x^2 + b*x^3 + c*x^4]),x]

[Out]

(-2*Sqrt[a]*(2*a - 3*b*x)*(a + x*(b + c*x)) - (3*b^2 - 4*a*c)*x^2*Sqrt[a + x*(b + c*x)]*ArcTanh[(2*a + b*x)/(2
*Sqrt[a]*Sqrt[a + x*(b + c*x)])])/(8*a^(5/2)*x*Sqrt[x^2*(a + x*(b + c*x))])

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IntegrateAlgebraic [A]  time = 0.44, size = 100, normalized size = 0.84 \begin {gather*} \frac {\left (3 b^2-4 a c\right ) \tanh ^{-1}\left (\frac {\sqrt {a} x}{\sqrt {c} x^2-\sqrt {a x^2+b x^3+c x^4}}\right )}{4 a^{5/2}}+\frac {(3 b x-2 a) \sqrt {a x^2+b x^3+c x^4}}{4 a^2 x^3} \end {gather*}

Antiderivative was successfully verified.

[In]

IntegrateAlgebraic[1/(x^2*Sqrt[a*x^2 + b*x^3 + c*x^4]),x]

[Out]

((-2*a + 3*b*x)*Sqrt[a*x^2 + b*x^3 + c*x^4])/(4*a^2*x^3) + ((3*b^2 - 4*a*c)*ArcTanh[(Sqrt[a]*x)/(Sqrt[c]*x^2 -
Sqrt[a*x^2 + b*x^3 + c*x^4])])/(4*a^(5/2))

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fricas [A]  time = 1.29, size = 232, normalized size = 1.95 \begin {gather*} \left [-\frac {{\left (3 \, b^{2} - 4 \, a c\right )} \sqrt {a} x^{3} \log \left (-\frac {8 \, a b x^{2} + {\left (b^{2} + 4 \, a c\right )} x^{3} + 8 \, a^{2} x + 4 \, \sqrt {c x^{4} + b x^{3} + a x^{2}} {\left (b x + 2 \, a\right )} \sqrt {a}}{x^{3}}\right ) - 4 \, \sqrt {c x^{4} + b x^{3} + a x^{2}} {\left (3 \, a b x - 2 \, a^{2}\right )}}{16 \, a^{3} x^{3}}, \frac {{\left (3 \, b^{2} - 4 \, a c\right )} \sqrt {-a} x^{3} \arctan \left (\frac {\sqrt {c x^{4} + b x^{3} + a x^{2}} {\left (b x + 2 \, a\right )} \sqrt {-a}}{2 \, {\left (a c x^{3} + a b x^{2} + a^{2} x\right )}}\right ) + 2 \, \sqrt {c x^{4} + b x^{3} + a x^{2}} {\left (3 \, a b x - 2 \, a^{2}\right )}}{8 \, a^{3} x^{3}}\right ] \end {gather*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(1/x^2/(c*x^4+b*x^3+a*x^2)^(1/2),x, algorithm="fricas")

[Out]

[-1/16*((3*b^2 - 4*a*c)*sqrt(a)*x^3*log(-(8*a*b*x^2 + (b^2 + 4*a*c)*x^3 + 8*a^2*x + 4*sqrt(c*x^4 + b*x^3 + a*x
^2)*(b*x + 2*a)*sqrt(a))/x^3) - 4*sqrt(c*x^4 + b*x^3 + a*x^2)*(3*a*b*x - 2*a^2))/(a^3*x^3), 1/8*((3*b^2 - 4*a*
c)*sqrt(-a)*x^3*arctan(1/2*sqrt(c*x^4 + b*x^3 + a*x^2)*(b*x + 2*a)*sqrt(-a)/(a*c*x^3 + a*b*x^2 + a^2*x)) + 2*s
qrt(c*x^4 + b*x^3 + a*x^2)*(3*a*b*x - 2*a^2))/(a^3*x^3)]

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giac [F(-2)]  time = 0.00, size = 0, normalized size = 0.00 \begin {gather*} \text {Exception raised: NotImplementedError} \end {gather*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(1/x^2/(c*x^4+b*x^3+a*x^2)^(1/2),x, algorithm="giac")

[Out]

Exception raised: NotImplementedError >> Unable to parse Giac output: Warning, choosing root of [1,0,%%%{-4,[1
,0,0,0]%%%}+%%%{-2,[0,1,0,1]%%%}+%%%{-2,[0,0,1,2]%%%},0,%%%{1,[0,2,0,2]%%%}+%%%{2,[0,1,1,3]%%%}+%%%{1,[0,0,2,4
]%%%}] at parameters values [54.7579903365,-49,-33,-70]2*(-4*a/16/a^2/x+6*b/16/a^2)*sqrt(a*(1/x)^2+b/x+c)+2*(-
4*a*c+3*b^2)/16/a^2/sqrt(a)*ln(abs(2*sqrt(a)*(sqrt(a*(1/x)^2+b/x+c)-sqrt(a)/x)-b))

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maple [A]  time = 0.01, size = 152, normalized size = 1.28 \begin {gather*} -\frac {\sqrt {c \,x^{2}+b x +a}\, \left (-4 a^{2} c \,x^{2} \ln \left (\frac {b x +2 a +2 \sqrt {c \,x^{2}+b x +a}\, \sqrt {a}}{x}\right )+3 a \,b^{2} x^{2} \ln \left (\frac {b x +2 a +2 \sqrt {c \,x^{2}+b x +a}\, \sqrt {a}}{x}\right )-6 \sqrt {c \,x^{2}+b x +a}\, a^{\frac {3}{2}} b x +4 \sqrt {c \,x^{2}+b x +a}\, a^{\frac {5}{2}}\right )}{8 \sqrt {c \,x^{4}+b \,x^{3}+a \,x^{2}}\, a^{\frac {7}{2}} x} \end {gather*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

int(1/x^2/(c*x^4+b*x^3+a*x^2)^(1/2),x)

[Out]

-1/8*(c*x^2+b*x+a)^(1/2)*(4*(c*x^2+b*x+a)^(1/2)*a^(5/2)-6*(c*x^2+b*x+a)^(1/2)*a^(3/2)*x*b-4*c*ln((b*x+2*a+2*(c
*x^2+b*x+a)^(1/2)*a^(1/2))/x)*x^2*a^2+3*ln((b*x+2*a+2*(c*x^2+b*x+a)^(1/2)*a^(1/2))/x)*x^2*a*b^2)/x/(c*x^4+b*x^
3+a*x^2)^(1/2)/a^(7/2)

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maxima [F]  time = 0.00, size = 0, normalized size = 0.00 \begin {gather*} \int \frac {1}{\sqrt {c x^{4} + b x^{3} + a x^{2}} x^{2}}\,{d x} \end {gather*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(1/x^2/(c*x^4+b*x^3+a*x^2)^(1/2),x, algorithm="maxima")

[Out]

integrate(1/(sqrt(c*x^4 + b*x^3 + a*x^2)*x^2), x)

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mupad [F]  time = 0.00, size = -1, normalized size = -0.01 \begin {gather*} \int \frac {1}{x^2\,\sqrt {c\,x^4+b\,x^3+a\,x^2}} \,d x \end {gather*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

int(1/(x^2*(a*x^2 + b*x^3 + c*x^4)^(1/2)),x)

[Out]

int(1/(x^2*(a*x^2 + b*x^3 + c*x^4)^(1/2)), x)

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sympy [F]  time = 0.00, size = 0, normalized size = 0.00 \begin {gather*} \int \frac {1}{x^{2} \sqrt {x^{2} \left (a + b x + c x^{2}\right )}}\, dx \end {gather*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(1/x**2/(c*x**4+b*x**3+a*x**2)**(1/2),x)

[Out]

Integral(1/(x**2*sqrt(x**2*(a + b*x + c*x**2))), x)

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