\(\int \frac {e^{2 \text {arctanh}(a x)} \sqrt {c-\frac {c}{a^2 x^2}}}{x^3} \, dx\) [808]

Optimal result

Integrand size = 27, antiderivative size = 103 \[ \int \frac {e^{2 \text {arctanh}(a x)} \sqrt {c-\frac {c}{a^2 x^2}}}{x^3} \, dx=-\frac {5}{3} a^2 \sqrt {c-\frac {c}{a^2 x^2}}-\frac {\sqrt {c-\frac {c}{a^2 x^2}}}{3 x^2}-\frac {a \sqrt {c-\frac {c}{a^2 x^2}}}{x}+a^2 \sqrt {c} \arctan \left (\frac {\sqrt {c}}{a \sqrt {c-\frac {c}{a^2 x^2}} x}\right ) \] Output:

-5/3*a^2*(c-c/a^2/x^2)^(1/2)-1/3*(c-c/a^2/x^2)^(1/2)/x^2-a*(c-c/a^2/x^2)^( 
1/2)/x+a^2*c^(1/2)*arctan(c^(1/2)/a/(c-c/a^2/x^2)^(1/2)/x)
                                                                                    
                                                                                    
 

Mathematica [A] (verified)

Time = 0.14 (sec) , antiderivative size = 71, normalized size of antiderivative = 0.69 \[ \int \frac {e^{2 \text {arctanh}(a x)} \sqrt {c-\frac {c}{a^2 x^2}}}{x^3} \, dx=\frac {\sqrt {c-\frac {c}{a^2 x^2}} \left (-1-3 a x-5 a^2 x^2+\frac {3 a^3 x^3 \arctan \left (\frac {1}{\sqrt {-1+a^2 x^2}}\right )}{\sqrt {-1+a^2 x^2}}\right )}{3 x^2} \] Input:

Integrate[(E^(2*ArcTanh[a*x])*Sqrt[c - c/(a^2*x^2)])/x^3,x]
 

Output:

(Sqrt[c - c/(a^2*x^2)]*(-1 - 3*a*x - 5*a^2*x^2 + (3*a^3*x^3*ArcTan[1/Sqrt[ 
-1 + a^2*x^2]])/Sqrt[-1 + a^2*x^2]))/(3*x^2)
 

Rubi [A] (verified)

Time = 0.71 (sec) , antiderivative size = 118, normalized size of antiderivative = 1.15, number of steps used = 11, number of rules used = 10, \(\frac {\text {number of rules}}{\text {integrand size}}\) = 0.370, Rules used = {6709, 540, 25, 27, 539, 27, 534, 243, 73, 221}

Below are the steps used by Rubi to obtain the solution. The rule number used for the transformation is given above next to the arrow. The rules definitions used are listed below.

\(\displaystyle \int \frac {e^{2 \text {arctanh}(a x)} \sqrt {c-\frac {c}{a^2 x^2}}}{x^3} \, dx\)

\(\Big \downarrow \) 6709

\(\displaystyle \frac {x \sqrt {c-\frac {c}{a^2 x^2}} \int \frac {(a x+1)^2}{x^4 \sqrt {1-a^2 x^2}}dx}{\sqrt {1-a^2 x^2}}\)

\(\Big \downarrow \) 540

\(\displaystyle \frac {x \sqrt {c-\frac {c}{a^2 x^2}} \left (-\frac {1}{3} \int -\frac {a (5 a x+6)}{x^3 \sqrt {1-a^2 x^2}}dx-\frac {\sqrt {1-a^2 x^2}}{3 x^3}\right )}{\sqrt {1-a^2 x^2}}\)

\(\Big \downarrow \) 25

\(\displaystyle \frac {x \sqrt {c-\frac {c}{a^2 x^2}} \left (\frac {1}{3} \int \frac {a (5 a x+6)}{x^3 \sqrt {1-a^2 x^2}}dx-\frac {\sqrt {1-a^2 x^2}}{3 x^3}\right )}{\sqrt {1-a^2 x^2}}\)

\(\Big \downarrow \) 27

\(\displaystyle \frac {x \sqrt {c-\frac {c}{a^2 x^2}} \left (\frac {1}{3} a \int \frac {5 a x+6}{x^3 \sqrt {1-a^2 x^2}}dx-\frac {\sqrt {1-a^2 x^2}}{3 x^3}\right )}{\sqrt {1-a^2 x^2}}\)

\(\Big \downarrow \) 539

\(\displaystyle \frac {x \sqrt {c-\frac {c}{a^2 x^2}} \left (\frac {1}{3} a \left (-\frac {1}{2} \int -\frac {2 a (3 a x+5)}{x^2 \sqrt {1-a^2 x^2}}dx-\frac {3 \sqrt {1-a^2 x^2}}{x^2}\right )-\frac {\sqrt {1-a^2 x^2}}{3 x^3}\right )}{\sqrt {1-a^2 x^2}}\)

\(\Big \downarrow \) 27

\(\displaystyle \frac {x \sqrt {c-\frac {c}{a^2 x^2}} \left (\frac {1}{3} a \left (a \int \frac {3 a x+5}{x^2 \sqrt {1-a^2 x^2}}dx-\frac {3 \sqrt {1-a^2 x^2}}{x^2}\right )-\frac {\sqrt {1-a^2 x^2}}{3 x^3}\right )}{\sqrt {1-a^2 x^2}}\)

\(\Big \downarrow \) 534

\(\displaystyle \frac {x \sqrt {c-\frac {c}{a^2 x^2}} \left (\frac {1}{3} a \left (a \left (3 a \int \frac {1}{x \sqrt {1-a^2 x^2}}dx-\frac {5 \sqrt {1-a^2 x^2}}{x}\right )-\frac {3 \sqrt {1-a^2 x^2}}{x^2}\right )-\frac {\sqrt {1-a^2 x^2}}{3 x^3}\right )}{\sqrt {1-a^2 x^2}}\)

\(\Big \downarrow \) 243

\(\displaystyle \frac {x \sqrt {c-\frac {c}{a^2 x^2}} \left (\frac {1}{3} a \left (a \left (\frac {3}{2} a \int \frac {1}{x^2 \sqrt {1-a^2 x^2}}dx^2-\frac {5 \sqrt {1-a^2 x^2}}{x}\right )-\frac {3 \sqrt {1-a^2 x^2}}{x^2}\right )-\frac {\sqrt {1-a^2 x^2}}{3 x^3}\right )}{\sqrt {1-a^2 x^2}}\)

\(\Big \downarrow \) 73

\(\displaystyle \frac {x \sqrt {c-\frac {c}{a^2 x^2}} \left (\frac {1}{3} a \left (a \left (-\frac {3 \int \frac {1}{\frac {1}{a^2}-\frac {x^4}{a^2}}d\sqrt {1-a^2 x^2}}{a}-\frac {5 \sqrt {1-a^2 x^2}}{x}\right )-\frac {3 \sqrt {1-a^2 x^2}}{x^2}\right )-\frac {\sqrt {1-a^2 x^2}}{3 x^3}\right )}{\sqrt {1-a^2 x^2}}\)

\(\Big \downarrow \) 221

\(\displaystyle \frac {x \left (\frac {1}{3} a \left (a \left (-3 a \text {arctanh}\left (\sqrt {1-a^2 x^2}\right )-\frac {5 \sqrt {1-a^2 x^2}}{x}\right )-\frac {3 \sqrt {1-a^2 x^2}}{x^2}\right )-\frac {\sqrt {1-a^2 x^2}}{3 x^3}\right ) \sqrt {c-\frac {c}{a^2 x^2}}}{\sqrt {1-a^2 x^2}}\)

Input:

Int[(E^(2*ArcTanh[a*x])*Sqrt[c - c/(a^2*x^2)])/x^3,x]
 

Output:

(Sqrt[c - c/(a^2*x^2)]*x*(-1/3*Sqrt[1 - a^2*x^2]/x^3 + (a*((-3*Sqrt[1 - a^ 
2*x^2])/x^2 + a*((-5*Sqrt[1 - a^2*x^2])/x - 3*a*ArcTanh[Sqrt[1 - a^2*x^2]] 
)))/3))/Sqrt[1 - a^2*x^2]
 

Defintions of rubi rules used

rule 25

Int[-(Fx_), x_Symbol] :> Simp[Identity[-1]   Int[Fx, x], x]
 

rule 27

Int[(a_)*(Fx_), x_Symbol] :> Simp[a   Int[Fx, x], x] /; FreeQ[a, x] &&  !Ma 
tchQ[Fx, (b_)*(Gx_) /; FreeQ[b, x]]
 

rule 73

Int[((a_.) + (b_.)*(x_))^(m_)*((c_.) + (d_.)*(x_))^(n_), x_Symbol] :> With[ 
{p = Denominator[m]}, Simp[p/b   Subst[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] && Lt 
Q[-1, m, 0] && LeQ[-1, n, 0] && LeQ[Denominator[n], Denominator[m]] && IntL 
inearQ[a, b, c, d, m, n, x]
 

rule 221

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

rule 243

Int[(x_)^(m_.)*((a_) + (b_.)*(x_)^2)^(p_), x_Symbol] :> Simp[1/2   Subst[In 
t[x^((m - 1)/2)*(a + b*x)^p, x], x, x^2], x] /; FreeQ[{a, b, m, p}, x] && I 
ntegerQ[(m - 1)/2]
 

rule 534

Int[(x_)^(m_)*((c_) + (d_.)*(x_))*((a_) + (b_.)*(x_)^2)^(p_), x_Symbol] :> 
Simp[(-c)*x^(m + 1)*((a + b*x^2)^(p + 1)/(2*a*(p + 1))), x] + Simp[d   Int[ 
x^(m + 1)*(a + b*x^2)^p, x], x] /; FreeQ[{a, b, c, d, m, p}, x] && ILtQ[m, 
0] && GtQ[p, -1] && EqQ[m + 2*p + 3, 0]
 

rule 539

Int[(x_)^(m_)*((c_) + (d_.)*(x_))*((a_) + (b_.)*(x_)^2)^(p_), x_Symbol] :> 
Simp[c*x^(m + 1)*((a + b*x^2)^(p + 1)/(a*(m + 1))), x] + Simp[1/(a*(m + 1)) 
   Int[x^(m + 1)*(a + b*x^2)^p*(a*d*(m + 1) - b*c*(m + 2*p + 3)*x), x], x] 
/; FreeQ[{a, b, c, d, p}, x] && ILtQ[m, -1] && GtQ[p, -1] && IntegerQ[2*p]
 

rule 540

Int[(x_)^(m_)*((c_) + (d_.)*(x_))^(n_)*((a_) + (b_.)*(x_)^2)^(p_), x_Symbol 
] :> With[{Qx = PolynomialQuotient[(c + d*x)^n, x, x], R = PolynomialRemain 
der[(c + d*x)^n, x, x]}, Simp[R*x^(m + 1)*((a + b*x^2)^(p + 1)/(a*(m + 1))) 
, x] + Simp[1/(a*(m + 1))   Int[x^(m + 1)*(a + b*x^2)^p*ExpandToSum[a*(m + 
1)*Qx - b*R*(m + 2*p + 3)*x, x], x], x]] /; FreeQ[{a, b, c, d, p}, x] && IG 
tQ[n, 1] && ILtQ[m, -1] && GtQ[p, -1] && IntegerQ[2*p]
 

rule 6709

Int[E^(ArcTanh[(a_.)*(x_)]*(n_.))*(u_.)*((c_) + (d_.)/(x_)^2)^(p_), x_Symbo 
l] :> Simp[x^(2*p)*((c + d/x^2)^p/(1 - a^2*x^2)^p)   Int[u*((1 + a*x)^n/(x^ 
(2*p)*(1 - a^2*x^2)^(n/2 - p))), x], x] /; FreeQ[{a, c, d, p}, x] && EqQ[c 
+ a^2*d, 0] &&  !IntegerQ[p] && IntegerQ[n/2] &&  !GtQ[c, 0]
 

Maple [A] (verified)

Time = 0.18 (sec) , antiderivative size = 150, normalized size of antiderivative = 1.46

method	result	size
risch	\(-\frac {\left (5 a^{4} x^{4}+3 a^{3} x^{3}-4 a^{2} x^{2}-3 a x -1\right ) \sqrt {\frac {c \left (a^{2} x^{2}-1\right )}{a^{2} x^{2}}}}{3 x^{2} \left (a^{2} x^{2}-1\right )}+\frac {a^{3} \ln \left (\frac {-2 c +2 \sqrt {-c}\, \sqrt {a^{2} c \,x^{2}-c}}{x}\right ) x \sqrt {c \left (a^{2} x^{2}-1\right )}\, \sqrt {\frac {c \left (a^{2} x^{2}-1\right )}{a^{2} x^{2}}}}{\sqrt {-c}\, \left (a^{2} x^{2}-1\right )}\)	\(150\)
default	\(\frac {\sqrt {\frac {c \left (a^{2} x^{2}-1\right )}{a^{2} x^{2}}}\, a \left (-6 \sqrt {\frac {c \left (a^{2} x^{2}-1\right )}{a^{2}}}\, \sqrt {-\frac {c}{a^{2}}}\, a^{3} c \,x^{4}+6 {\left (\frac {c \left (a^{2} x^{2}-1\right )}{a^{2}}\right )}^{\frac {3}{2}} \sqrt {-\frac {c}{a^{2}}}\, a^{3} x^{2}+3 \sqrt {\frac {c \left (a^{2} x^{2}-1\right )}{a^{2}}}\, \sqrt {-\frac {c}{a^{2}}}\, a^{2} c \,x^{3}+6 \sqrt {-\frac {c}{a^{2}}}\, c^{\frac {3}{2}} \ln \left (x \sqrt {c}+\sqrt {\frac {c \left (a^{2} x^{2}-1\right )}{a^{2}}}\right ) a \,x^{3}-6 \sqrt {-\frac {c}{a^{2}}}\, c^{\frac {3}{2}} \ln \left (\frac {\sqrt {c}\, \sqrt {\frac {c \left (a x -1\right ) \left (a x +1\right )}{a^{2}}}+x c}{\sqrt {c}}\right ) a \,x^{3}-6 \sqrt {-\frac {c}{a^{2}}}\, \sqrt {\frac {c \left (a x -1\right ) \left (a x +1\right )}{a^{2}}}\, a^{2} c \,x^{3}+3 {\left (\frac {c \left (a^{2} x^{2}-1\right )}{a^{2}}\right )}^{\frac {3}{2}} \sqrt {-\frac {c}{a^{2}}}\, a^{2} x +3 \ln \left (\frac {2 \sqrt {-\frac {c}{a^{2}}}\, \sqrt {\frac {c \left (a^{2} x^{2}-1\right )}{a^{2}}}\, a^{2}-2 c}{a^{2} x}\right ) c^{2} x^{3}+a {\left (\frac {c \left (a^{2} x^{2}-1\right )}{a^{2}}\right )}^{\frac {3}{2}} \sqrt {-\frac {c}{a^{2}}}\right )}{3 x^{2} \sqrt {\frac {c \left (a^{2} x^{2}-1\right )}{a^{2}}}\, \sqrt {-\frac {c}{a^{2}}}\, c}\)	\(378\)

Input:

int((a*x+1)^2/(-a^2*x^2+1)*(c-c/a^2/x^2)^(1/2)/x^3,x,method=_RETURNVERBOSE 
)
 

Output:

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

Fricas [A] (verification not implemented)

Time = 0.11 (sec) , antiderivative size = 186, normalized size of antiderivative = 1.81 \[ \int \frac {e^{2 \text {arctanh}(a x)} \sqrt {c-\frac {c}{a^2 x^2}}}{x^3} \, dx=\left [\frac {3 \, a^{2} \sqrt {-c} x^{2} \log \left (-\frac {a^{2} c x^{2} - 2 \, a \sqrt {-c} x \sqrt {\frac {a^{2} c x^{2} - c}{a^{2} x^{2}}} - 2 \, c}{x^{2}}\right ) - 2 \, {\left (5 \, a^{2} x^{2} + 3 \, a x + 1\right )} \sqrt {\frac {a^{2} c x^{2} - c}{a^{2} x^{2}}}}{6 \, x^{2}}, -\frac {3 \, a^{2} \sqrt {c} x^{2} \arctan \left (\frac {a x \sqrt {\frac {a^{2} c x^{2} - c}{a^{2} x^{2}}}}{\sqrt {c}}\right ) + {\left (5 \, a^{2} x^{2} + 3 \, a x + 1\right )} \sqrt {\frac {a^{2} c x^{2} - c}{a^{2} x^{2}}}}{3 \, x^{2}}\right ] \] Input:

integrate((a*x+1)^2/(-a^2*x^2+1)*(c-c/a^2/x^2)^(1/2)/x^3,x, algorithm="fri 
cas")
 

Output:

[1/6*(3*a^2*sqrt(-c)*x^2*log(-(a^2*c*x^2 - 2*a*sqrt(-c)*x*sqrt((a^2*c*x^2 
- c)/(a^2*x^2)) - 2*c)/x^2) - 2*(5*a^2*x^2 + 3*a*x + 1)*sqrt((a^2*c*x^2 - 
c)/(a^2*x^2)))/x^2, -1/3*(3*a^2*sqrt(c)*x^2*arctan(a*x*sqrt((a^2*c*x^2 - c 
)/(a^2*x^2))/sqrt(c)) + (5*a^2*x^2 + 3*a*x + 1)*sqrt((a^2*c*x^2 - c)/(a^2* 
x^2)))/x^2]
 

Sympy [F]

\[ \int \frac {e^{2 \text {arctanh}(a x)} \sqrt {c-\frac {c}{a^2 x^2}}}{x^3} \, dx=- \int \frac {\sqrt {c - \frac {c}{a^{2} x^{2}}}}{a x^{4} - x^{3}}\, dx - \int \frac {a x \sqrt {c - \frac {c}{a^{2} x^{2}}}}{a x^{4} - x^{3}}\, dx \] Input:

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

Output:

-Integral(sqrt(c - c/(a**2*x**2))/(a*x**4 - x**3), x) - Integral(a*x*sqrt( 
c - c/(a**2*x**2))/(a*x**4 - x**3), x)
 

Maxima [F]

\[ \int \frac {e^{2 \text {arctanh}(a x)} \sqrt {c-\frac {c}{a^2 x^2}}}{x^3} \, dx=\int { -\frac {{\left (a x + 1\right )}^{2} \sqrt {c - \frac {c}{a^{2} x^{2}}}}{{\left (a^{2} x^{2} - 1\right )} x^{3}} \,d x } \] Input:

integrate((a*x+1)^2/(-a^2*x^2+1)*(c-c/a^2/x^2)^(1/2)/x^3,x, algorithm="max 
ima")
 

Output:

-1/3*(2*a^2*sqrt(c)*x^2 + sqrt(c))*sqrt(a*x + 1)*sqrt(a*x - 1)/(a*x^3) - i 
ntegrate((a*sqrt(c)*x + 2*sqrt(c))*sqrt(a*x + 1)*sqrt(a*x - 1)/(a^2*x^5 - 
x^3), x)
 

Giac [B] (verification not implemented)

Leaf count of result is larger than twice the leaf count of optimal. 231 vs. \(2 (87) = 174\).

Time = 0.17 (sec) , antiderivative size = 231, normalized size of antiderivative = 2.24 \[ \int \frac {e^{2 \text {arctanh}(a x)} \sqrt {c-\frac {c}{a^2 x^2}}}{x^3} \, dx=-\frac {2}{3} \, {\left (3 \, a \sqrt {c} \arctan \left (-\frac {\sqrt {a^{2} c} x - \sqrt {a^{2} c x^{2} - c}}{\sqrt {c}}\right ) \mathrm {sgn}\left (x\right ) - \frac {3 \, {\left (\sqrt {a^{2} c} x - \sqrt {a^{2} c x^{2} - c}\right )}^{5} a c \mathrm {sgn}\left (x\right ) - 3 \, {\left (\sqrt {a^{2} c} x - \sqrt {a^{2} c x^{2} - c}\right )}^{4} c^{\frac {3}{2}} {\left | a \right |} \mathrm {sgn}\left (x\right ) - 12 \, {\left (\sqrt {a^{2} c} x - \sqrt {a^{2} c x^{2} - c}\right )}^{2} c^{\frac {5}{2}} {\left | a \right |} \mathrm {sgn}\left (x\right ) - 3 \, {\left (\sqrt {a^{2} c} x - \sqrt {a^{2} c x^{2} - c}\right )} a c^{3} \mathrm {sgn}\left (x\right ) - 5 \, c^{\frac {7}{2}} {\left | a \right |} \mathrm {sgn}\left (x\right )}{{\left ({\left (\sqrt {a^{2} c} x - \sqrt {a^{2} c x^{2} - c}\right )}^{2} + c\right )}^{3}}\right )} {\left | a \right |} \] Input:

integrate((a*x+1)^2/(-a^2*x^2+1)*(c-c/a^2/x^2)^(1/2)/x^3,x, algorithm="gia 
c")
 

Output:

-2/3*(3*a*sqrt(c)*arctan(-(sqrt(a^2*c)*x - sqrt(a^2*c*x^2 - c))/sqrt(c))*s 
gn(x) - (3*(sqrt(a^2*c)*x - sqrt(a^2*c*x^2 - c))^5*a*c*sgn(x) - 3*(sqrt(a^ 
2*c)*x - sqrt(a^2*c*x^2 - c))^4*c^(3/2)*abs(a)*sgn(x) - 12*(sqrt(a^2*c)*x 
- sqrt(a^2*c*x^2 - c))^2*c^(5/2)*abs(a)*sgn(x) - 3*(sqrt(a^2*c)*x - sqrt(a 
^2*c*x^2 - c))*a*c^3*sgn(x) - 5*c^(7/2)*abs(a)*sgn(x))/((sqrt(a^2*c)*x - s 
qrt(a^2*c*x^2 - c))^2 + c)^3)*abs(a)
 

Mupad [F(-1)]

Timed out. \[ \int \frac {e^{2 \text {arctanh}(a x)} \sqrt {c-\frac {c}{a^2 x^2}}}{x^3} \, dx=-\int \frac {\sqrt {c-\frac {c}{a^2\,x^2}}\,{\left (a\,x+1\right )}^2}{x^3\,\left (a^2\,x^2-1\right )} \,d x \] Input:

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

Output:

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

Reduce [B] (verification not implemented)

Time = 0.15 (sec) , antiderivative size = 86, normalized size of antiderivative = 0.83 \[ \int \frac {e^{2 \text {arctanh}(a x)} \sqrt {c-\frac {c}{a^2 x^2}}}{x^3} \, dx=\frac {\sqrt {c}\, \left (-6 \mathit {atan} \left (\sqrt {a^{2} x^{2}-1}+a x \right ) a^{3} x^{3}-5 \sqrt {a^{2} x^{2}-1}\, a^{2} x^{2}-3 \sqrt {a^{2} x^{2}-1}\, a x -\sqrt {a^{2} x^{2}-1}+3 a^{3} x^{3}\right )}{3 a \,x^{3}} \] Input:

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

Output:

(sqrt(c)*( - 6*atan(sqrt(a**2*x**2 - 1) + a*x)*a**3*x**3 - 5*sqrt(a**2*x** 
2 - 1)*a**2*x**2 - 3*sqrt(a**2*x**2 - 1)*a*x - sqrt(a**2*x**2 - 1) + 3*a** 
3*x**3))/(3*a*x**3)