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Viewing Version 32 of 'list of improper integrals'
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Title of object: list of improper integrals
Canonical Name: ListOfImproperIntegrals
Type: Topic

Created on: 2009-01-10 08:31:04
Modified on: 2009-01-23 18:49:27

Creator: pahio
Modifier: pahio
Author: pahio
Author: gel

Classification: msc:40A10
Keywords: improper integral

Revision comment (for changes between this and next version):

generalisation of 5

Preamble:

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% it should be fine as is for beginners.

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\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsfonts}

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%\usepackage{psfrag}
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%\usepackage{graphicx}
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\theoremstyle{definition}
\newtheorem*{thmplain}{Theorem}
Content:

\PMlinkid{1.}{7065} \; $\displaystyle\int_0^\infty e^{-x^2}\,dx \;=\; \frac{\sqrt{\pi}}{2}$\\

\PMlinkid{2.}{11495} \; $\displaystyle\int_0^\infty e^{-x^2}\cos{kx}\,dx\;=\;\frac{\sqrt{\pi}}{2}e^{-\frac{1}{4}k^2}$\\

\PMlinkid{3.}{11504} \; $\displaystyle\int_0^\infty \frac{e^{-x^2}}{a^2\!+\!x^2}\,dx
\;=\;\frac{\pi}{2a}e^{a^2}\,{\rm erfc}\,a$\\

\PMlinkid{4.}{10980} \; $\displaystyle\int_0^\infty\sin{x^2}\,dx \;=\; \int_0^\infty\cos{x^2}\,dx \;=\;
\frac{\sqrt{2\pi}}{4}$\\

\PMlinkid{5.}{7082} \; $\displaystyle\int_0^\infty\frac{\sin{x}}{x}\,dx \;=\; \frac{\pi}{2}$\\

\PMlinkid{6.}{11487} \; $\displaystyle\int_0^\infty\left(\frac{\sin{x}}{x}\right)^2 dx \;=\; \frac{\pi}{2}$\\

\PMlinkid{7.}{11487} \; $\displaystyle\int_0^\infty\frac{1-\cos{kx}}{x^2}\,dx \;=\; \frac{\pi k}{2}$\\

\PMlinkid{8.}{11480} \; $\displaystyle\int_0^\infty\frac{x^{-k}}{x\!+\!1}\,dx \;=\; \frac{\pi}{\sin{\pi k}}
\quad (0 < k < 1)$\\

\PMlinkid{9.}{11544} \; $\displaystyle\int_{-\infty}^\infty\frac{e^{kx}}{1\!+\!e^x}\,dx \;=\; \frac{\pi}{\sin{\pi k}}
\quad (0 < k < 1)$\\


\PMlinkid{10.}{7136} \; $\displaystyle\int_0^\infty\frac{\cos{kx}}{x^2\!+\!1}\,dx \;=\; \frac{\pi}{2e^k}$\\

\PMlinkid{11.}{11489} \; $\displaystyle\int_0^\infty\frac{a\cos{x}}{x^2\!+\!a^2}\,dx
\;=\; \int_0^\infty\frac{x\sin{x}}{x^2\!+\!a^2}\,dx \;=\; \frac{\pi}{2e^a} \quad\; (a > 0)$\\

12. \; $\displaystyle\int_0^\infty\frac{\sin{ax}}{x(x^2\!+\!1)}\,dx \;=\; \frac{\pi}{2}(1-e^{-a}) \quad\; (a > 0)$\\

\PMlinkid{13.}{9223} \; $\displaystyle\int_0^\infty e^{-x}x^{-\frac{3}{2}}\,dx \;=\; \sqrt{\pi}$\\

\PMlinkid{14.}{10637} \; $\displaystyle\int_0^\infty e^{-x}x^3\sin{x}\,dx \;=\; 0$\\

\PMlinkid{15.}{7891} \; $\displaystyle\int_0^\infty\!\left(\frac{1}{e^x-1}-\frac{1}{xe^x}\right) dx \;=\; \gamma$\\

\PMlinkid{16.}{11516} \; $\displaystyle\int_0^\infty\!\frac{\cos{ax^2}-\cos{ax}}{x} dx \;=\; \frac{\gamma+\ln{a}}{2} \quad (a > 0)$\\

\PMlinkid{17.}{11511} \; $\displaystyle\int_0^\infty\frac{e^{-ax}\!-\!e^{-bx}}{x}\,dx \;=\; \ln\frac{b}{a} \quad (a > 0,\;\, b > 0)$\\

\PMlinkid{18.}{11526} \; $\displaystyle\int_1^\infty\left(\arcsin\frac{1}{x}-\frac{1}{x}\right)\,dx \;=\; 1+\ln{2}-\frac{\pi}{2}$\\