Integrand size = 31, antiderivative size = 166 \[ \int \frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{x} \, dx=-8 \sqrt {1-\sqrt {1-\sqrt {\frac {-1+x}{x}}}}+2 \sqrt {-1+\sqrt {2}} \arctan \left (\frac {\sqrt {1-\sqrt {1-\sqrt {\frac {-1+x}{x}}}}}{\sqrt {-1+\sqrt {2}}}\right )+4 \text {arctanh}\left (\sqrt {1-\sqrt {1-\sqrt {\frac {-1+x}{x}}}}\right )+2 \sqrt {1+\sqrt {2}} \text {arctanh}\left (\frac {\sqrt {1-\sqrt {1-\sqrt {\frac {-1+x}{x}}}}}{\sqrt {1+\sqrt {2}}}\right ) \]
-8*(1-(1-((-1+x)/x)^(1/2))^(1/2))^(1/2)+2*(2^(1/2)-1)^(1/2)*arctan((1-(1-( (-1+x)/x)^(1/2))^(1/2))^(1/2)/(2^(1/2)-1)^(1/2))+4*arctanh((1-(1-((-1+x)/x )^(1/2))^(1/2))^(1/2))+2*(1+2^(1/2))^(1/2)*arctanh((1-(1-((-1+x)/x)^(1/2)) ^(1/2))^(1/2)/(1+2^(1/2))^(1/2))
Time = 0.29 (sec) , antiderivative size = 166, normalized size of antiderivative = 1.00 \[ \int \frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{x} \, dx=-8 \sqrt {1-\sqrt {1-\sqrt {\frac {-1+x}{x}}}}+2 \sqrt {-1+\sqrt {2}} \arctan \left (\sqrt {1+\sqrt {2}} \sqrt {1-\sqrt {1-\sqrt {\frac {-1+x}{x}}}}\right )+4 \text {arctanh}\left (\sqrt {1-\sqrt {1-\sqrt {\frac {-1+x}{x}}}}\right )+2 \sqrt {1+\sqrt {2}} \text {arctanh}\left (\sqrt {-1+\sqrt {2}} \sqrt {1-\sqrt {1-\sqrt {\frac {-1+x}{x}}}}\right ) \]
-8*Sqrt[1 - Sqrt[1 - Sqrt[(-1 + x)/x]]] + 2*Sqrt[-1 + Sqrt[2]]*ArcTan[Sqrt [1 + Sqrt[2]]*Sqrt[1 - Sqrt[1 - Sqrt[(-1 + x)/x]]]] + 4*ArcTanh[Sqrt[1 - S qrt[1 - Sqrt[(-1 + x)/x]]]] + 2*Sqrt[1 + Sqrt[2]]*ArcTanh[Sqrt[-1 + Sqrt[2 ]]*Sqrt[1 - Sqrt[1 - Sqrt[(-1 + x)/x]]]]
Time = 1.10 (sec) , antiderivative size = 312, normalized size of antiderivative = 1.88, number of steps used = 15, number of rules used = 14, \(\frac {\text {number of rules}}{\text {integrand size}}\) = 0.452, Rules used = {7268, 7267, 2003, 2351, 481, 25, 561, 654, 25, 1480, 217, 219, 1610, 2009}
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.
\(\displaystyle \int \frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{x} \, dx\) |
\(\Big \downarrow \) 7268 |
\(\displaystyle 2 \int \sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}} \sqrt {1-\frac {1}{x}} xd\sqrt {1-\frac {1}{x}}\) |
\(\Big \downarrow \) 7267 |
\(\displaystyle -4 \int \frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{\sqrt {1-\frac {1}{x}} \left (1+\frac {1}{x}\right ) x}d\sqrt {1-\sqrt {1-\frac {1}{x}}}\) |
\(\Big \downarrow \) 2003 |
\(\displaystyle -4 \int \frac {\left (1-\sqrt {1-\sqrt {1-\frac {1}{x}}}\right )^{3/2} \left (\sqrt {1-\sqrt {1-\frac {1}{x}}}+1\right )}{\sqrt {1-\frac {1}{x}} \left (1+\frac {1}{x}\right )}d\sqrt {1-\sqrt {1-\frac {1}{x}}}\) |
\(\Big \downarrow \) 2351 |
\(\displaystyle -4 \left (\int \frac {\left (1-\sqrt {1-\sqrt {1-\frac {1}{x}}}\right )^{3/2}}{1+\frac {1}{x}}d\sqrt {1-\sqrt {1-\frac {1}{x}}}+\int \frac {\left (1-\sqrt {1-\sqrt {1-\frac {1}{x}}}\right )^{3/2}}{\sqrt {1-\frac {1}{x}} \left (1+\frac {1}{x}\right )}d\sqrt {1-\sqrt {1-\frac {1}{x}}}\right )\) |
\(\Big \downarrow \) 481 |
\(\displaystyle -4 \left (-\int -\frac {3-2 \sqrt {1-\sqrt {1-\frac {1}{x}}}}{\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}} \left (1+\frac {1}{x}\right )}d\sqrt {1-\sqrt {1-\frac {1}{x}}}+\int \frac {\left (1-\sqrt {1-\sqrt {1-\frac {1}{x}}}\right )^{3/2}}{\sqrt {1-\frac {1}{x}} \left (1+\frac {1}{x}\right )}d\sqrt {1-\sqrt {1-\frac {1}{x}}}+2 \sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}\right )\) |
\(\Big \downarrow \) 25 |
\(\displaystyle -4 \left (\int \frac {3-2 \sqrt {1-\sqrt {1-\frac {1}{x}}}}{\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}} \left (1+\frac {1}{x}\right )}d\sqrt {1-\sqrt {1-\frac {1}{x}}}+\int \frac {\left (1-\sqrt {1-\sqrt {1-\frac {1}{x}}}\right )^{3/2}}{\sqrt {1-\frac {1}{x}} \left (1+\frac {1}{x}\right )}d\sqrt {1-\sqrt {1-\frac {1}{x}}}+2 \sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}\right )\) |
\(\Big \downarrow \) 561 |
\(\displaystyle -4 \left (\int \frac {3-2 \sqrt {1-\sqrt {1-\frac {1}{x}}}}{\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}} \left (1+\frac {1}{x}\right )}d\sqrt {1-\sqrt {1-\frac {1}{x}}}-2 \int \frac {\left (1-\frac {1}{x}\right )^2 x}{-\left (1-\frac {1}{x}\right )^2+2 \left (1-\frac {1}{x}\right )+1}d\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}+2 \sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}\right )\) |
\(\Big \downarrow \) 654 |
\(\displaystyle -4 \left (2 \int -\frac {2 \left (1-\frac {1}{x}\right )+1}{-\left (1-\frac {1}{x}\right )^2+2 \left (1-\frac {1}{x}\right )+1}d\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}-2 \int \frac {\left (1-\frac {1}{x}\right )^2 x}{-\left (1-\frac {1}{x}\right )^2+2 \left (1-\frac {1}{x}\right )+1}d\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}+2 \sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}\right )\) |
\(\Big \downarrow \) 25 |
\(\displaystyle -4 \left (-2 \int \frac {2 \left (1-\frac {1}{x}\right )+1}{-\left (1-\frac {1}{x}\right )^2+2 \left (1-\frac {1}{x}\right )+1}d\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}-2 \int \frac {\left (1-\frac {1}{x}\right )^2 x}{-\left (1-\frac {1}{x}\right )^2+2 \left (1-\frac {1}{x}\right )+1}d\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}+2 \sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}\right )\) |
\(\Big \downarrow \) 1480 |
\(\displaystyle -4 \left (2 \left (-\frac {1}{4} \left (4-3 \sqrt {2}\right ) \int \frac {1}{\frac {1}{x}-\sqrt {2}}d\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}-\frac {1}{4} \left (4+3 \sqrt {2}\right ) \int \frac {1}{\sqrt {2}+\frac {1}{x}}d\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}\right )-2 \int \frac {\left (1-\frac {1}{x}\right )^2 x}{-\left (1-\frac {1}{x}\right )^2+2 \left (1-\frac {1}{x}\right )+1}d\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}+2 \sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}\right )\) |
\(\Big \downarrow \) 217 |
\(\displaystyle -4 \left (2 \left (\frac {\left (4-3 \sqrt {2}\right ) \arctan \left (\frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{\sqrt {\sqrt {2}-1}}\right )}{4 \sqrt {\sqrt {2}-1}}-\frac {1}{4} \left (4+3 \sqrt {2}\right ) \int \frac {1}{\sqrt {2}+\frac {1}{x}}d\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}\right )-2 \int \frac {\left (1-\frac {1}{x}\right )^2 x}{-\left (1-\frac {1}{x}\right )^2+2 \left (1-\frac {1}{x}\right )+1}d\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}+2 \sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}\right )\) |
\(\Big \downarrow \) 219 |
\(\displaystyle -4 \left (-2 \int \frac {\left (1-\frac {1}{x}\right )^2 x}{-\left (1-\frac {1}{x}\right )^2+2 \left (1-\frac {1}{x}\right )+1}d\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}+2 \left (\frac {\left (4-3 \sqrt {2}\right ) \arctan \left (\frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{\sqrt {\sqrt {2}-1}}\right )}{4 \sqrt {\sqrt {2}-1}}-\frac {\left (4+3 \sqrt {2}\right ) \text {arctanh}\left (\frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{\sqrt {1+\sqrt {2}}}\right )}{4 \sqrt {1+\sqrt {2}}}\right )+2 \sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}\right )\) |
\(\Big \downarrow \) 1610 |
\(\displaystyle -4 \left (-2 \int \left (\frac {3 \left (1-\frac {1}{x}\right )+1}{2 \left (\left (1-\frac {1}{x}\right )^2-2 \left (1-\frac {1}{x}\right )-1\right )}+\frac {x}{2}\right )d\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}+2 \left (\frac {\left (4-3 \sqrt {2}\right ) \arctan \left (\frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{\sqrt {\sqrt {2}-1}}\right )}{4 \sqrt {\sqrt {2}-1}}-\frac {\left (4+3 \sqrt {2}\right ) \text {arctanh}\left (\frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{\sqrt {1+\sqrt {2}}}\right )}{4 \sqrt {1+\sqrt {2}}}\right )+2 \sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}\right )\) |
\(\Big \downarrow \) 2009 |
\(\displaystyle -4 \left (2 \left (\frac {\left (4-3 \sqrt {2}\right ) \arctan \left (\frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{\sqrt {\sqrt {2}-1}}\right )}{4 \sqrt {\sqrt {2}-1}}-\frac {\left (4+3 \sqrt {2}\right ) \text {arctanh}\left (\frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{\sqrt {1+\sqrt {2}}}\right )}{4 \sqrt {1+\sqrt {2}}}\right )-2 \left (\frac {1}{4} \sqrt {5 \sqrt {2}-7} \arctan \left (\frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{\sqrt {\sqrt {2}-1}}\right )+\frac {1}{2} \text {arctanh}\left (\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}\right )-\frac {1}{4} \sqrt {7+5 \sqrt {2}} \text {arctanh}\left (\frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{\sqrt {1+\sqrt {2}}}\right )\right )+2 \sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}\right )\) |
-4*(2*Sqrt[1 - Sqrt[1 - Sqrt[1 - x^(-1)]]] + 2*(((4 - 3*Sqrt[2])*ArcTan[Sq rt[1 - Sqrt[1 - Sqrt[1 - x^(-1)]]]/Sqrt[-1 + Sqrt[2]]])/(4*Sqrt[-1 + Sqrt[ 2]]) - ((4 + 3*Sqrt[2])*ArcTanh[Sqrt[1 - Sqrt[1 - Sqrt[1 - x^(-1)]]]/Sqrt[ 1 + Sqrt[2]]])/(4*Sqrt[1 + Sqrt[2]])) - 2*((Sqrt[-7 + 5*Sqrt[2]]*ArcTan[Sq rt[1 - Sqrt[1 - Sqrt[1 - x^(-1)]]]/Sqrt[-1 + Sqrt[2]]])/4 + ArcTanh[Sqrt[1 - Sqrt[1 - Sqrt[1 - x^(-1)]]]]/2 - (Sqrt[7 + 5*Sqrt[2]]*ArcTanh[Sqrt[1 - Sqrt[1 - Sqrt[1 - x^(-1)]]]/Sqrt[1 + Sqrt[2]]])/4))
3.23.24.3.1 Defintions of rubi rules used
Int[((a_) + (b_.)*(x_)^2)^(-1), x_Symbol] :> Simp[(-(Rt[-a, 2]*Rt[-b, 2])^( -1))*ArcTan[Rt[-b, 2]*(x/Rt[-a, 2])], x] /; FreeQ[{a, b}, x] && PosQ[a/b] & & (LtQ[a, 0] || LtQ[b, 0])
Int[((a_) + (b_.)*(x_)^2)^(-1), x_Symbol] :> Simp[(1/(Rt[a, 2]*Rt[-b, 2]))* ArcTanh[Rt[-b, 2]*(x/Rt[a, 2])], x] /; FreeQ[{a, b}, x] && NegQ[a/b] && (Gt Q[a, 0] || LtQ[b, 0])
Int[((c_) + (d_.)*(x_))^(n_)/((a_) + (b_.)*(x_)^2), x_Symbol] :> Simp[d*((c + d*x)^(n - 1)/(b*(n - 1))), x] + Simp[1/b Int[(c + d*x)^(n - 2)*(Simp[b *c^2 - a*d^2 + 2*b*c*d*x, x]/(a + b*x^2)), x], x] /; FreeQ[{a, b, c, d}, x] && GtQ[n, 1]
Int[(x_)^(m_.)*((c_) + (d_.)*(x_))^(n_)*((a_) + (b_.)*(x_)^2)^(p_), x_Symbo l] :> With[{k = Denominator[n]}, Simp[k/d Subst[Int[x^(k*(n + 1) - 1)*(-c /d + x^k/d)^m*Simp[(b*c^2 + a*d^2)/d^2 - 2*b*c*(x^k/d^2) + b*(x^(2*k)/d^2), x]^p, x], x, (c + d*x)^(1/k)], x]] /; FreeQ[{a, b, c, d, m, p}, x] && Frac tionQ[n] && IntegerQ[p] && IntegerQ[m]
Int[((f_.) + (g_.)*(x_))/(Sqrt[(d_.) + (e_.)*(x_)]*((a_) + (c_.)*(x_)^2)), x_Symbol] :> Simp[2 Subst[Int[(e*f - d*g + g*x^2)/(c*d^2 + a*e^2 - 2*c*d* x^2 + c*x^4), x], x, Sqrt[d + e*x]], x] /; FreeQ[{a, c, d, e, f, g}, x]
Int[((d_) + (e_.)*(x_)^2)/((a_) + (b_.)*(x_)^2 + (c_.)*(x_)^4), x_Symbol] : > With[{q = Rt[b^2 - 4*a*c, 2]}, Simp[(e/2 + (2*c*d - b*e)/(2*q)) Int[1/( b/2 - q/2 + c*x^2), x], x] + Simp[(e/2 - (2*c*d - b*e)/(2*q)) Int[1/(b/2 + q/2 + c*x^2), x], x]] /; FreeQ[{a, b, c, d, e}, x] && NeQ[b^2 - 4*a*c, 0] && NeQ[c*d^2 - a*e^2, 0] && PosQ[b^2 - 4*a*c]
Int[(((f_.)*(x_))^(m_.)*((d_) + (e_.)*(x_)^2)^(q_.))/((a_) + (b_.)*(x_)^2 + (c_.)*(x_)^4), x_Symbol] :> Int[ExpandIntegrand[(f*x)^m*((d + e*x^2)^q/(a + b*x^2 + c*x^4)), x], x] /; FreeQ[{a, b, c, d, e, f, m}, x] && NeQ[b^2 - 4 *a*c, 0] && IntegerQ[q] && IntegerQ[m]
Int[(u_)*((c_) + (d_.)*(x_))^(n_.)*((a_) + (b_.)*(x_)^2)^(p_.), x_Symbol] : > Int[u*(c + d*x)^(n + p)*(a/c + (b/d)*x)^p, x] /; FreeQ[{a, b, c, d, n, p} , x] && EqQ[b*c^2 + a*d^2, 0] && (IntegerQ[p] || (GtQ[a, 0] && GtQ[c, 0] && !IntegerQ[n]))
Int[((Px_)*((c_) + (d_.)*(x_))^(n_.)*((a_) + (b_.)*(x_)^2)^(p_.))/(x_), x_S ymbol] :> Int[PolynomialQuotient[Px, x, x]*(c + d*x)^n*(a + b*x^2)^p, x] + Simp[PolynomialRemainder[Px, x, x] Int[(c + d*x)^n*((a + b*x^2)^p/x), x], x] /; FreeQ[{a, b, c, d, n, p}, x] && PolynomialQ[Px, x]
Int[u_, x_Symbol] :> With[{lst = SubstForFractionalPowerOfLinear[u, x]}, Si mp[lst[[2]]*lst[[4]] Subst[Int[lst[[1]], x], x, lst[[3]]^(1/lst[[2]])], x ] /; !FalseQ[lst] && SubstForFractionalPowerQ[u, lst[[3]], x]]
Int[u_, x_Symbol] :> With[{lst = SubstForFractionalPowerOfQuotientOfLinears [u, x]}, Simp[lst[[2]]*lst[[4]] Subst[Int[lst[[1]], x], x, lst[[3]]^(1/ls t[[2]])], x] /; !FalseQ[lst]]
\[\int \frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{x}d x\]
Leaf count of result is larger than twice the leaf count of optimal. 253 vs. \(2 (126) = 252\).
Time = 0.25 (sec) , antiderivative size = 253, normalized size of antiderivative = 1.52 \[ \int \frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{x} \, dx=\sqrt {\sqrt {2} + 1} \log \left (2 \, \sqrt {\sqrt {2} + 1} + 2 \, \sqrt {-\sqrt {-\sqrt {\frac {x - 1}{x}} + 1} + 1}\right ) - \sqrt {\sqrt {2} + 1} \log \left (-2 \, \sqrt {\sqrt {2} + 1} + 2 \, \sqrt {-\sqrt {-\sqrt {\frac {x - 1}{x}} + 1} + 1}\right ) + \frac {1}{2} \, \sqrt {-4 \, \sqrt {2} + 4} \log \left (\sqrt {-4 \, \sqrt {2} + 4} + 2 \, \sqrt {-\sqrt {-\sqrt {\frac {x - 1}{x}} + 1} + 1}\right ) - \frac {1}{2} \, \sqrt {-4 \, \sqrt {2} + 4} \log \left (-\sqrt {-4 \, \sqrt {2} + 4} + 2 \, \sqrt {-\sqrt {-\sqrt {\frac {x - 1}{x}} + 1} + 1}\right ) - 8 \, \sqrt {-\sqrt {-\sqrt {\frac {x - 1}{x}} + 1} + 1} + 2 \, \log \left (\sqrt {-\sqrt {-\sqrt {\frac {x - 1}{x}} + 1} + 1} + 1\right ) - 2 \, \log \left (\sqrt {-\sqrt {-\sqrt {\frac {x - 1}{x}} + 1} + 1} - 1\right ) \]
sqrt(sqrt(2) + 1)*log(2*sqrt(sqrt(2) + 1) + 2*sqrt(-sqrt(-sqrt((x - 1)/x) + 1) + 1)) - sqrt(sqrt(2) + 1)*log(-2*sqrt(sqrt(2) + 1) + 2*sqrt(-sqrt(-sq rt((x - 1)/x) + 1) + 1)) + 1/2*sqrt(-4*sqrt(2) + 4)*log(sqrt(-4*sqrt(2) + 4) + 2*sqrt(-sqrt(-sqrt((x - 1)/x) + 1) + 1)) - 1/2*sqrt(-4*sqrt(2) + 4)*l og(-sqrt(-4*sqrt(2) + 4) + 2*sqrt(-sqrt(-sqrt((x - 1)/x) + 1) + 1)) - 8*sq rt(-sqrt(-sqrt((x - 1)/x) + 1) + 1) + 2*log(sqrt(-sqrt(-sqrt((x - 1)/x) + 1) + 1) + 1) - 2*log(sqrt(-sqrt(-sqrt((x - 1)/x) + 1) + 1) - 1)
\[ \int \frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{x} \, dx=\int \frac {\sqrt {1 - \sqrt {1 - \sqrt {1 - \frac {1}{x}}}}}{x}\, dx \]
\[ \int \frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{x} \, dx=\int { \frac {\sqrt {-\sqrt {-\sqrt {-\frac {1}{x} + 1} + 1} + 1}}{x} \,d x } \]
\[ \int \frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{x} \, dx=\int { \frac {\sqrt {-\sqrt {-\sqrt {-\frac {1}{x} + 1} + 1} + 1}}{x} \,d x } \]
Timed out. \[ \int \frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{x} \, dx=\int \frac {\sqrt {1-\sqrt {1-\sqrt {1-\frac {1}{x}}}}}{x} \,d x \]