Integration of exp(-az)*sigma(t-to)*dz ??

*To*: mathgroup at smc.vnet.net*Subject*: [mg5378] Integration of exp(-az)*sigma(t-to)*dz ??*From*: esfahani at mikro.ee.tu-berlin.de (Farzad Esfahani)*Date*: Thu, 5 Dec 1996 14:50:19 -0500*Organization*: Technical University Berlin, Germany*Sender*: owner-wri-mathgroup at wolfram.com

Hello you all, I have to solve the following integration, who can help me or give me some hints? I(t) = A * Integral(from z=zo until oo) exp(-a*z) * sigma(t - to) dz Where: My actual problem is to find a way to integrate the step function sigma. Is there any possiblities to approximate it to a mathematical function. Or is there any rule for its integration that I am not aware of it. I have already looked in some Math books but I didn't find it. PS1: Please let me know whether there are also other newsgroups dealing with Ps2: Please send me your responses via e-mail, since I don't read this Thanks in advance Farzad