IntegerQ
- To: mathgroup at smc.vnet.net
- Subject: [mg8024] IntegerQ
- From: "K. Nikolaj Berntsen" <knb at bkm.dtu.dk>
- Date: Sat, 2 Aug 1997 22:32:34 -0400
- Organization: News Server at UNI-C, Danish Computing Centre for Research and Education.
- Sender: owner-wri-mathgroup at wolfram.com
If this is posted twice, please forgive me; I posted it yesterday and it
has not appeared yet, so I try by another channel.
I am looking for a way to tell mathematica that "n" is an integer AND to
use that piece of information.
I have tried something like
In[]= n /: IntegerQ[n]=True
Out[]= True
But this does not seem to get through to mathematica, other than when
you explicitely ask the question
In[]= IntegerQ[n]
For example mathematica cannot do the following:
In[]= Sin[n Pi]
Out[]= 0
Of course I do not really care for the above identity, but I do want to
carry out an integration like
Integrate[Exp[Cos[x]] Cos[n x],{x,0,2 Pi}]
Mathematica can do this for any "n" I have come with, but it can not
give
me the general expression (well sometimes it can, in the beginning of a
notebook).
Another example would be to get
Integrate[Cos[x]^n,{x,0,2 Pi}]
In the same form as (or whatever integer you choose to put in)
Integrate[Cos[x]^3,{x,0,2 Pi}]
Maybe it would be necessary to tell mathematica that it is an even or
odd number, but that does not seem to help it out:
In[]= n/: EvenQ[n]=True
Out[]= True
In[]= Integrate[Cos[x]^n,{x,0,2 Pi}]
Anybody out there who has as way to do it?
Regards,
Nikolaj
--------------------------------------------------------------
| Ph.D. stud., cand.scient. |
| K. Nikolaj Berntsen |
| Office: Department of Structural Engineering and Materials |
| Technical University of Denmark |
| Building 118, room 152 |
| DK-2800 Lyngby |
| Tel +45 4525 1769 |
| Fax +45 4588 3282 |
| Email: knb at bkm.dtu.dk |
| URL: http://www.bkm.dtu.dk/~knb |
-------------------------------------------------------------