Re: integration problem???
- To: mathgroup at smc.vnet.net
- Subject: [mg9282] Re: [mg9257] integration problem???
- From: Allan Hayes <hay at haystack.demon.co.uk>
- Date: Mon, 27 Oct 1997 02:46:53 -0500
- Sender: owner-wri-mathgroup at wolfram.com
"J. M. Reese" <eng484 at eng.abdn.ac.uk> [mg9257] integration problem???
writes
>I am trying to integrate the expression: ((2*r2-r1-r).^5).*(r.^(-8))
> with respect to r, between the limits r1=4.75e-4 to r2=2.25e-4.
>
> If I use Mathematica I get 1.9567e10 If I use quad8 in Matlab I get
> 1.156e07
Jason:
With Mathematica 3.0 on a NeXt and on a Mac I get answers consistent
with the Matlab answer.
r1 =4.75 10^-4;r2=2.25 10^-4;
Integrate[((2*r2-r1-r)^5)*(r^(-8)),{r,r1,r2}]
1.156406983991509*^7
NIntegrate[((2*r2-r1-r)^5)*(r^(-8)),{r,r1,r2}]
1.15640698399151*^7
r1 =475 10^-6;r2=225 10^-6;
The exact answer is
Integrate[ ((2*r2-r1-r)^5)*(r^(-8)),{r,r1,r2}]
346083997600000000000000/29927525723291637
Which gives
N[%]
1.156406983991509*^7
Allan Hayes
hay at haystack.demon.co.uk
http://www.haystack.demon.co.uk/training.html voice:+44 (0)116 2714198
fax: +44 (0)116 2718642
Leicester, UK