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 Jul12 awarded Nice Question Jul5 revised Solve inhomogeneous wave equation improved notation formatting Jul5 suggested approved edit on Solve inhomogeneous wave equation Jul5 revised Find a single-valued analytic branch of $\sqrt{z^2-1}$ in $\mathbb{C} \backslash [-1,1]$. fixed format Jul5 suggested approved edit on Find a single-valued analytic branch of $\sqrt{z^2-1}$ in $\mathbb{C} \backslash [-1,1]$. Jul5 comment Evaluating $\int\limits_{-\infty}^\infty {\exp(iax)\over1+ix}dx$ This looks like the Fourier Transform. Jul5 revised Differentiation under the integral sign. improved formatting. Jul5 suggested approved edit on Differentiation under the integral sign. Jun30 revised Gauss-Hermite quadrature of $\cos(x)$ over infinity Improved Formatting Jun30 suggested approved edit on Gauss-Hermite quadrature of $\cos(x)$ over infinity Jun30 comment How to find the eccentricity of this conic? What level are you asking this question from,... is this a pre-calculus course? Just so the responses and terminology would be more appropriate for your level. If so, you might want to tag your question with pre-calculus or the related as well. Jun30 comment Laplace transform of $1/t$ Or more simply: $t^n \stackrel{\mathcal{L}}{\Longleftrightarrow} \frac{n!}{s^{n+1}}$ without involving the gamma ($\:\Gamma\:$) function. Jun28 comment Evaluation of these integrals @draks: Of course not :D, using a CAS. Is it possible to get polylog function by hand or recognize it from doing intergrals? I just thought this was a CAS algorithmic way of deducing the problem into a more complex answer using special functions, because an elementary table look up failed. So it resorted to special solution techniques. Although $\tan k$ is considered a simple function but not sure about hyperbolic tangent :) Jun28 comment Evaluation of these integrals I get this for integral one: Not sure if equivalent to Norbet answers. $\int_0^p \! ktanh(\pi k)=-(1/24)(-\pi^2+12p^2\pi^2-24p\ln(1+exp(2p\pi))\pi-12polylog(2,-exp(2p\pi)))/(‌​\pi^2)$ Jun28 comment Solving a complex integral Similar type of question from a $\mathbb{R}$ domain standpoint. math.stackexchange.com/questions/73250/… Jun28 comment Fundamental solution of the wave operator Have a look here for starts: math.ucsd.edu/~lindblad/110b/l17.pdf math.ucsd.edu/~lindblad/110b/l18.pdf Jun8 awarded Constituent Jun8 awarded Caucus Apr29 accepted Definition of Sinc function Apr29 comment Definition of Sinc function Very nice answer. :)