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To: Neil Booth who wrote (32649)	3/22/2001 5:52:51 AM
From: fyodor_	Read Replies (1) \| Respond to of 275872

Neil: Do you have an example from physics of delta meaning the difference between two different things? I don't think so. Sure I do!!! RANDOM BOOK from my bookshelf: Introduction to the structure of Matter, John J. Brehm & William J. Mullin. RANDOM PAGE (I'll admit a bit of luck on this bit): (144) (I'm going to write an uppercase delta as DELTA in the following) DELTA N / N0 = INTEGRAL (n/A0 * dsigma / dSIGMA) dSIGMA = ... blah blah blah We then find DN = 4pi .... = 0.179 alpha particles per second (this particular calculation was on simple Rutherford scattering) NEXT RANDOM BOOK: Physics of Atoms and Molecules, B.H. Bransden and C.J. Joachain RANDOM PAGE (yes, it really was... I'll admit to a lot of luck again): (458) The chapter is on molecular spectra, specifically doublets (specifically the inversion spectrum of ammonia). PSI(z,t) = c1 * phi1(z) * exp(-(i/hbar)E1t) + c2 phi2(z) * exp(-(i/hbar)E2t) where E2 = E1 + DELTA E (DELTA E being the energy splitting of the doublet) Would you care to see any more examples? Or do you think I'm making all this crap up? If so, I'd be happy to scan the pages and upload them e.g. at a geocities page. P.S. Ok, I found a good online example: Theoretical Neuroscience by Peter Dayan and LF Abbott. Look at, e.g., chapter 1 page 21: play.ccs.brandeis.edu Middle of page. --- 1/M SIGMA ( S(m)S(m+p)) = sigma(s) sigma(s) / DELTA t if p=0, otherwise 0. The factor of 1/DELTA t on the right side of this equation reproduces the delta function of equation 1.24 in the limit of DELTA t --> 0. blah blah blah --- More examples? No? Are you sure? Ok, then. I'll keep f'n using DELTA as meaning difference. ;p -fyo