3.163 \(\int \log (a \sin ^n(x)) \, dx\)

Optimal. Leaf size=52 \[ \frac{1}{2} i n \text{PolyLog}\left (2,e^{2 i x}\right )+x \log \left (a \sin ^n(x)\right )+\frac{1}{2} i n x^2-n x \log \left (1-e^{2 i x}\right ) \]

[Out]

(I/2)*n*x^2 - n*x*Log[1 - E^((2*I)*x)] + x*Log[a*Sin[x]^n] + (I/2)*n*PolyLog[2, E^((2*I)*x)]

________________________________________________________________________________________

Rubi [A]  time = 0.0598711, antiderivative size = 52, normalized size of antiderivative = 1., number of steps used = 6, number of rules used = 6, integrand size = 7, \(\frac{\text{number of rules}}{\text{integrand size}}\) = 0.857, Rules used = {2548, 12, 3717, 2190, 2279, 2391} \[ \frac{1}{2} i n \text{PolyLog}\left (2,e^{2 i x}\right )+x \log \left (a \sin ^n(x)\right )+\frac{1}{2} i n x^2-n x \log \left (1-e^{2 i x}\right ) \]

Antiderivative was successfully verified.

[In]

Int[Log[a*Sin[x]^n],x]

[Out]

(I/2)*n*x^2 - n*x*Log[1 - E^((2*I)*x)] + x*Log[a*Sin[x]^n] + (I/2)*n*PolyLog[2, E^((2*I)*x)]

Rule 2548

Int[Log[u_], x_Symbol] :> Simp[x*Log[u], x] - Int[SimplifyIntegrand[(x*D[u, x])/u, x], x] /; InverseFunctionFr
eeQ[u, x]

Rule 12

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

Rule 3717

Int[((c_.) + (d_.)*(x_))^(m_.)*tan[(e_.) + Pi*(k_.) + (f_.)*(x_)], x_Symbol] :> Simp[(I*(c + d*x)^(m + 1))/(d*
(m + 1)), x] - Dist[2*I, Int[((c + d*x)^m*E^(2*I*k*Pi)*E^(2*I*(e + f*x)))/(1 + E^(2*I*k*Pi)*E^(2*I*(e + f*x)))
, x], x] /; FreeQ[{c, d, e, f}, x] && IntegerQ[4*k] && IGtQ[m, 0]

Rule 2190

Int[(((F_)^((g_.)*((e_.) + (f_.)*(x_))))^(n_.)*((c_.) + (d_.)*(x_))^(m_.))/((a_) + (b_.)*((F_)^((g_.)*((e_.) +
(f_.)*(x_))))^(n_.)), x_Symbol] :> Simp[((c + d*x)^m*Log[1 + (b*(F^(g*(e + f*x)))^n)/a])/(b*f*g*n*Log[F]), x]
- Dist[(d*m)/(b*f*g*n*Log[F]), Int[(c + d*x)^(m - 1)*Log[1 + (b*(F^(g*(e + f*x)))^n)/a], x], x] /; FreeQ[{F,
a, b, c, d, e, f, g, n}, x] && IGtQ[m, 0]

Rule 2279

Int[Log[(a_) + (b_.)*((F_)^((e_.)*((c_.) + (d_.)*(x_))))^(n_.)], x_Symbol] :> Dist[1/(d*e*n*Log[F]), Subst[Int
[Log[a + b*x]/x, x], x, (F^(e*(c + d*x)))^n], x] /; FreeQ[{F, a, b, c, d, e, n}, x] && GtQ[a, 0]

Rule 2391

Int[Log[(c_.)*((d_) + (e_.)*(x_)^(n_.))]/(x_), x_Symbol] :> -Simp[PolyLog[2, -(c*e*x^n)]/n, x] /; FreeQ[{c, d,
e, n}, x] && EqQ[c*d, 1]

Rubi steps

\begin{align*} \int \log \left (a \sin ^n(x)\right ) \, dx &=x \log \left (a \sin ^n(x)\right )-\int n x \cot (x) \, dx\\ &=x \log \left (a \sin ^n(x)\right )-n \int x \cot (x) \, dx\\ &=\frac{1}{2} i n x^2+x \log \left (a \sin ^n(x)\right )+(2 i n) \int \frac{e^{2 i x} x}{1-e^{2 i x}} \, dx\\ &=\frac{1}{2} i n x^2-n x \log \left (1-e^{2 i x}\right )+x \log \left (a \sin ^n(x)\right )+n \int \log \left (1-e^{2 i x}\right ) \, dx\\ &=\frac{1}{2} i n x^2-n x \log \left (1-e^{2 i x}\right )+x \log \left (a \sin ^n(x)\right )-\frac{1}{2} (i n) \operatorname{Subst}\left (\int \frac{\log (1-x)}{x} \, dx,x,e^{2 i x}\right )\\ &=\frac{1}{2} i n x^2-n x \log \left (1-e^{2 i x}\right )+x \log \left (a \sin ^n(x)\right )+\frac{1}{2} i n \text{Li}_2\left (e^{2 i x}\right )\\ \end{align*}

Mathematica [A]  time = 0.0235813, size = 52, normalized size = 1. \[ \frac{1}{2} i n \text{PolyLog}\left (2,e^{2 i x}\right )+x \log \left (a \sin ^n(x)\right )+\frac{1}{2} i n x^2-n x \log \left (1-e^{2 i x}\right ) \]

Antiderivative was successfully verified.

[In]

Integrate[Log[a*Sin[x]^n],x]

[Out]

(I/2)*n*x^2 - n*x*Log[1 - E^((2*I)*x)] + x*Log[a*Sin[x]^n] + (I/2)*n*PolyLog[2, E^((2*I)*x)]

________________________________________________________________________________________

Maple [F]  time = 0.177, size = 0, normalized size = 0. \begin{align*} \int \ln \left ( a \left ( \sin \left ( x \right ) \right ) ^{n} \right ) \, dx \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

int(ln(a*sin(x)^n),x)

[Out]

int(ln(a*sin(x)^n),x)

________________________________________________________________________________________

Maxima [B]  time = 2.13966, size = 123, normalized size = 2.37 \begin{align*} -\frac{1}{2} \,{\left (-i \, x^{2} + 2 i \, x \arctan \left (\sin \left (x\right ), \cos \left (x\right ) + 1\right ) - 2 i \, x \arctan \left (\sin \left (x\right ), -\cos \left (x\right ) + 1\right ) + x \log \left (\cos \left (x\right )^{2} + \sin \left (x\right )^{2} + 2 \, \cos \left (x\right ) + 1\right ) + x \log \left (\cos \left (x\right )^{2} + \sin \left (x\right )^{2} - 2 \, \cos \left (x\right ) + 1\right ) - 2 i \,{\rm Li}_2\left (-e^{\left (i \, x\right )}\right ) - 2 i \,{\rm Li}_2\left (e^{\left (i \, x\right )}\right )\right )} n + x \log \left (a \sin \left (x\right )^{n}\right ) \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(log(a*sin(x)^n),x, algorithm="maxima")

[Out]

-1/2*(-I*x^2 + 2*I*x*arctan2(sin(x), cos(x) + 1) - 2*I*x*arctan2(sin(x), -cos(x) + 1) + x*log(cos(x)^2 + sin(x
)^2 + 2*cos(x) + 1) + x*log(cos(x)^2 + sin(x)^2 - 2*cos(x) + 1) - 2*I*dilog(-e^(I*x)) - 2*I*dilog(e^(I*x)))*n
+ x*log(a*sin(x)^n)

________________________________________________________________________________________

Fricas [B]  time = 2.11214, size = 433, normalized size = 8.33 \begin{align*} -\frac{1}{2} \, n x \log \left (\cos \left (x\right ) + i \, \sin \left (x\right ) + 1\right ) - \frac{1}{2} \, n x \log \left (\cos \left (x\right ) - i \, \sin \left (x\right ) + 1\right ) - \frac{1}{2} \, n x \log \left (-\cos \left (x\right ) + i \, \sin \left (x\right ) + 1\right ) - \frac{1}{2} \, n x \log \left (-\cos \left (x\right ) - i \, \sin \left (x\right ) + 1\right ) + n x \log \left (\sin \left (x\right )\right ) + \frac{1}{2} i \, n{\rm Li}_2\left (\cos \left (x\right ) + i \, \sin \left (x\right )\right ) - \frac{1}{2} i \, n{\rm Li}_2\left (\cos \left (x\right ) - i \, \sin \left (x\right )\right ) - \frac{1}{2} i \, n{\rm Li}_2\left (-\cos \left (x\right ) + i \, \sin \left (x\right )\right ) + \frac{1}{2} i \, n{\rm Li}_2\left (-\cos \left (x\right ) - i \, \sin \left (x\right )\right ) + x \log \left (a\right ) \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(log(a*sin(x)^n),x, algorithm="fricas")

[Out]

-1/2*n*x*log(cos(x) + I*sin(x) + 1) - 1/2*n*x*log(cos(x) - I*sin(x) + 1) - 1/2*n*x*log(-cos(x) + I*sin(x) + 1)
- 1/2*n*x*log(-cos(x) - I*sin(x) + 1) + n*x*log(sin(x)) + 1/2*I*n*dilog(cos(x) + I*sin(x)) - 1/2*I*n*dilog(co
s(x) - I*sin(x)) - 1/2*I*n*dilog(-cos(x) + I*sin(x)) + 1/2*I*n*dilog(-cos(x) - I*sin(x)) + x*log(a)

________________________________________________________________________________________

Sympy [F]  time = 0., size = 0, normalized size = 0. \begin{align*} \int \log{\left (a \sin ^{n}{\left (x \right )} \right )}\, dx \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(ln(a*sin(x)**n),x)

[Out]

Integral(log(a*sin(x)**n), x)

________________________________________________________________________________________

Giac [F]  time = 0., size = 0, normalized size = 0. \begin{align*} \int \log \left (a \sin \left (x\right )^{n}\right )\,{d x} \end{align*}

Verification of antiderivative is not currently implemented for this CAS.

[In]

integrate(log(a*sin(x)^n),x, algorithm="giac")

[Out]

integrate(log(a*sin(x)^n), x)