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
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                         |
-------------------------------------------------------------

```

• Prev by Date: 3D plot of bitmap???
• Next by Date: [Q] Printing on Brother HL-10h
• Previous by thread: Re: 3D plot of bitmap???
• Next by thread: [Q] Printing on Brother HL-10h