i've tried to Evaluate $$\int_{0}^{\frac{\pi}{6}}x\ln^2(2\sin(x))dx$$ without using Contour integral first i changed $2\sin(x)$ into polar form ,and i got $$\int_{0}^{\frac{\pi}{6}}x\ln^2(2\sin(x))dx = \Re(\int_{0}^{\frac{\pi}{6}}x\ln^2(1-e^{2ix})dx)+\int_{0}^{\frac{\pi}{6}} x(x-\frac{\pi}{2})^2 dx $$ then to find $$\Re(\int_{0}^{\frac{\pi}{6}}x\ln^2(1-e^{2ix})dx)$$ So i used Harmonic Number identities $$\sum_{n=1}^{\infty} \frac{H_{n}x^{n+1}}{(n+1)} = \frac{\ln^2(1-x)}{2}$$ then substituted $x$ with $e^{2ix}$ and multiply x on both sides and take an integral $$\int_{0}^{\frac{\pi}{6}}\sum_{n=1}^{\infty} \frac{e^{2i(n+1)x}xH_n}{n+1} = \frac{1}{2}\int_{0}^{\frac{\pi}{6}}x\ln^2(1-e^{2ix})dx $$ and considered only real part $$ \Re(\frac{1}{2}\int_{0}^{\frac{\pi}{6}}x\ln^2(1-e^{2ix})dx) = \Re(\sum_{n=1}^{\infty} \frac{H_{n}}{n+1}\bigg[\frac{e^{\frac{i\pi(n+1)}{3}}(2i\pi(n+1))-6}{-24(n+1)^2} \bigg])$$ So i got $$\Re(\sum_{n=1}^{\infty} \frac{H_{n}}{n+1}\bigg[\frac{e^{\frac{i\pi(n+1)}{3}}(2i\pi(n+1))-6}{-24(n+1)^2} \bigg]) = \frac{1}{4}\bigg[\sum_{n=1}^{\infty}\frac{H_{n}\cos(\frac{\pi(n+1)}{3})}{(n+1)^3}-\sum_{n=1}^{\infty}\frac{H_{n}}{(n+1)^3}\bigg]+\sum_{n=1}^{\infty}\frac{H_{n}\sin(\frac{\pi(n+1)}{3})}{12(n+1)^2}$$ last but not least,So i change $\cos(\frac{\pi(n+1)}{3})$ into a polar form again then i've no idea How to evaluate it properly with out any huge expansion So i think i might need to use $$\sum_{n=1}^{\infty} \frac{{H_n}x^{n+1}}{(n+1)^3}$$ to complete the whole progress ,but i'm stuck at this point Could someone give me a hand please.
2026-03-25 14:24:39.1774448679
Generalized form of this Harmonic Number series $\sum_{n=1}^{\infty} \frac{{H_n}x^{n+1}}{(n+1)^3}$
120 Views Asked by Bumbble Comm https://math.techqa.club/user/bumbble-comm/detail AtRelated Questions in REAL-ANALYSIS
- how is my proof on equinumerous sets
- Finding radius of convergence $\sum _{n=0}^{}(2+(-1)^n)^nz^n$
- Optimization - If the sum of objective functions are similar, will sum of argmax's be similar
- On sufficient condition for pre-compactness "in measure"(i.e. in Young measure space)
- Justify an approximation of $\sum_{n=1}^\infty G_n/\binom{\frac{n}{2}+\frac{1}{2}}{\frac{n}{2}}$, where $G_n$ denotes the Gregory coefficients
- Calculating the radius of convergence for $\sum _{n=1}^{\infty}\frac{\left(\sqrt{ n^2+n}-\sqrt{n^2+1}\right)^n}{n^2}z^n$
- Is this relating to continuous functions conjecture correct?
- What are the functions satisfying $f\left(2\sum_{i=0}^{\infty}\frac{a_i}{3^i}\right)=\sum_{i=0}^{\infty}\frac{a_i}{2^i}$
- Absolutely continuous functions are dense in $L^1$
- A particular exercise on convergence of recursive sequence
Related Questions in SUMMATION
- Computing:$\sum_{n=0}^\infty\frac{3^n}{n!(n+3)}$
- Prove that $1+{1\over 1+{1\over 1+{1\over 1+{1\over 1+...}}}}=\sqrt{1+\sqrt{1+\sqrt{1+\sqrt{1+...}}}}$
- Fourier series. Find the sum $\sum_{n=1}^\infty \frac{(-1)^{n+1}}{2n+1}$
- Sigma (sum) Problem
- How to prove the inequality $\frac{1}{n}+\frac{1}{n+1}+\cdots+\frac{1}{2n-1}\geq \log (2)$?
- Double-exponential sum (maybe it telescopes?)
- Simplify $\prod_{k=1}^{l} \sum_{r=d}^m {{m}\choose{r}} \left(N-k \right)^{r} k^{m-r+1}$
- Sum of two martingales
- How can we prove that $e^{-jωn}$ converges at $0$ while n -> infinity?
- Interesting inequalities
Related Questions in HARMONIC-NUMBERS
- A Gift Problem for the Year 2018
- Hypergeometric series with harmonic factor
- Infinite series with harmonic numbers related to elliptic integrals
- A non obvious example of a sequence $a(k)\cdot H_{b(k)}$ whose general term is integer many times, where $H_n$ denotes the $n$th harmonic number
- On integer sequences of the form $\sum_{n=1}^N (a(n))^2H_n^2,$ where $H_n$ is the $n$th harmonic number: refute my conjecture and add yourself example
- Simple formula for $H_n = m + \alpha $?
- Limit of the difference between two harmonic numbers
- Justify an approximation of $-\sum_{n=2}^\infty H_n\left(\frac{1}{\zeta(n)}-1\right)$, where $H_n$ denotes the $n$th harmonic number
- Show that for $n\gt 2$, $\frac{\sigma_1(n)}{n}\lt H_n$
- first derivative of exponential generating function of harmonic numbers
Related Questions in POLYLOGARITHM
- Evaluate $\int_0^1 \frac{\mathrm{d}x}{\sqrt{1-x^2}}\frac{x }{1-k^2x^2}\log\left(\frac{1-x}{1+x}\right)$
- A surprising dilogarithm integral identity arising from a generalised point enclosure problem
- Polylogarithms: How to prove the asympotic expression $ z \le \mathrm{Li}_{s}(z) \le z(1+2z 2^{-s}), \;z<-1, \;s \gg \log_2|z|$
- Bose-Einstein function as real part of polylogarithm: $\overline{G}_{s}(x)= \Re \mathrm{Li}_{s+1}(e^x)$
- Jump of dilogarithm
- About the integral $\int\arctan\left(\frac{1}{\sinh^2 x}\right)dx$, some idea or feedback
- Approaching a branch point along different paths
- Evaluation of : $ \int_{0}^{1}\frac{\log^2 (x+1)}{x}$?
- The indefinite integral $\int\frac{\operatorname{Li}_2(x)}{1+\sqrt{x}}\,dx$: what is the strategy to get such indefinite integral
- Definite integral involving a log and a rational function.
Trending Questions
- Induction on the number of equations
- How to convince a math teacher of this simple and obvious fact?
- Find $E[XY|Y+Z=1 ]$
- Refuting the Anti-Cantor Cranks
- What are imaginary numbers?
- Determine the adjoint of $\tilde Q(x)$ for $\tilde Q(x)u:=(Qu)(x)$ where $Q:U→L^2(Ω,ℝ^d$ is a Hilbert-Schmidt operator and $U$ is a Hilbert space
- Why does this innovative method of subtraction from a third grader always work?
- How do we know that the number $1$ is not equal to the number $-1$?
- What are the Implications of having VΩ as a model for a theory?
- Defining a Galois Field based on primitive element versus polynomial?
- Can't find the relationship between two columns of numbers. Please Help
- Is computer science a branch of mathematics?
- Is there a bijection of $\mathbb{R}^n$ with itself such that the forward map is connected but the inverse is not?
- Identification of a quadrilateral as a trapezoid, rectangle, or square
- Generator of inertia group in function field extension
Popular # Hahtags
second-order-logic
numerical-methods
puzzle
logic
probability
number-theory
winding-number
real-analysis
integration
calculus
complex-analysis
sequences-and-series
proof-writing
set-theory
functions
homotopy-theory
elementary-number-theory
ordinary-differential-equations
circles
derivatives
game-theory
definite-integrals
elementary-set-theory
limits
multivariable-calculus
geometry
algebraic-number-theory
proof-verification
partial-derivative
algebra-precalculus
Popular Questions
- What is the integral of 1/x?
- How many squares actually ARE in this picture? Is this a trick question with no right answer?
- Is a matrix multiplied with its transpose something special?
- What is the difference between independent and mutually exclusive events?
- Visually stunning math concepts which are easy to explain
- taylor series of $\ln(1+x)$?
- How to tell if a set of vectors spans a space?
- Calculus question taking derivative to find horizontal tangent line
- How to determine if a function is one-to-one?
- Determine if vectors are linearly independent
- What does it mean to have a determinant equal to zero?
- Is this Batman equation for real?
- How to find perpendicular vector to another vector?
- How to find mean and median from histogram
- How many sides does a circle have?