Something wrong with this integral (see text)

*To*: mathgroup at smc.vnet.net*Subject*: [mg44403] Something wrong with this integral (see text)*From*: "Ihor Stealth" <stealth at gmx.net>*Date*: Sat, 8 Nov 2003 04:50:47 -0500 (EST)*Organization*: Eindhoven University of Technology, The Netherlands*Sender*: owner-wri-mathgroup at wolfram.com

Hi All I calculated two expressions: FullSimplify[Integrate[(-L^2)/(L^2 + 1)*Cos[L], {L,0, Infinity}]] and FullSimplify[Integrate[(-1)/(L^2 + 1)*Cos[L], {L,0, Infinity}]] They gave the same result, but in the first expression when we take L->Infinity, it's impossible to take integral, but MAthematica CAN do that. What the explanation of this? Tnx for any help. Ihor