RE: Re: how to explain this weird effect? Integrate

*To*: mathgroup at smc.vnet.net*Subject*: [mg46431] RE: [mg46411] Re: how to explain this weird effect? Integrate*From*: "David Park" <djmp at earthlink.net>*Date*: Wed, 18 Feb 2004 00:36:54 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Steve, And it's nice when Mathematica can do things like that. But there is also a matter of efficiency. Value substitutions are quite common in Mathematica. They also occur whenever you write a routine with arguments, or a With statement. If Mathematica has to check if the expression has singular values, and if the substitution creates one of those singular values, and then has to try various kinds of limits, it's going to become very convoluted and slow down EVERYTHING. Maybe in the future when we get quantum computers and more advanced algorithms we'll see more of what you hope for. And already Mathematica has added extra capability with Assuming and the Assumptions options. David Park djmp at earthlink.net http://home.earthlink.net/~djmp/ From: steve_H [mailto:nma124 at hotmail.com] To: mathgroup at smc.vnet.net But that is exactly my point. I wanted Mathematica to act as if it was a human. (A very smart human at that). All what I am saying is that Mathematica should have taken that extra step without me having to tell. The way I look at it, is that when I tell a computer algebra program to solve X, then I expect the program to do what it can and apply any number of different steps and 'tricks' to solve X. I do not have to tell it to do step 1 first, then step 2, then if it can't do step 2, then try this trick first, and then do step 2, etc... All what iam saying is that taking the limit in this case is NOT an additional step becuase it would have lead to the solution I wanted. I guess it is a design issue. Some folks here do not seem to agree with this, but I think this is how a computer algebra system should work. So, may be we should drop this subject and leave it at that. We agree to diagree. regards, Steve