Re: Definite integral

*To*: mathgroup at smc.vnet.net*Subject*: [mg88468] Re: Definite integral*From*: Szabolcs Horvát <szhorvat at gmail.com>*Date*: Tue, 6 May 2008 06:39:04 -0400 (EDT)*Organization*: University of Bergen*References*: <fvmmrd$8ef$1@smc.vnet.net>

Miguel wrote: > I don't understand Mathematica can't calculate the last definite > integral. For the first three integrals works fine, but for the last > one crush. You can see in this paper > > http://mathematicaes.googlegroups.com/web/Curves.pdf?gda=7zTXujoAAAA-whg7foWysEERSilJsIeVif4THE-OC9pisLLDECe8l5BwmXXnNsFOempl8HAl8JkHsusoMR-tRlq_vv1lRgeh&gsc=CGn5gQsAAABmIpg7U95zHJwjbRxzLtsD This is because you typed \[Epsilon] instead of \[Element]. This works fine: Integrate[3/2 Sqrt[Sin[2 x]^2], {x, 3 Pi/2, t}, Assumptions -> 2 Pi > t > (3 Pi)/2] It is not necessary to separately specify that variables used in inequalities are reals. But if you do, use x \[Element] Reals or Element[x, Reals], but *not* x \[Epsilon] Reals. The two symbols have nothing to do with each other! So this is one more reason why the ugly lunate epsilon should not be used in mathematics ... I never understood why American/English textbooks were so fond of this symbol (never seen it in any Eastern European books).