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Re: Need Help

• To: mathgroup at smc.vnet.net
• Subject: [mg94690] Re: Need Help
• From: "Oyedeji, Kale" <koyedeji at morehouse.edu>
• Date: Sat, 20 Dec 2008 06:22:18 -0500 (EST)
• References: <200812181222.HAA00451@smc.vnet.net> <gig3m7$2ee$1@smc.vnet.net> <494C8A9F.5090306@gmail.com>

I thank Jean-Marc, Daniel, Bob, and Bill for all your assistance. All your suggestions worked perfectly. It  took me a while to see the source of the error was in not placing a semi-colon before the comma in R[k + 1] = f*S[k]*R[k];,

Thank you all for your time.

'Kale

-----Original Message-----
From: Jean-Marc Gulliet [mailto:jeanmarc.gulliet at gmail.com] 
Sent: Saturday, December 20, 2008 1:03 AM
To: Oyedeji, Kale; mathgroup at smc.vnet.net
Subject: [mg94690] Re: Need Help

Oyedeji, Kale wrote:

> Bill, thanks for your comment. I have two iterative implicit functions
> S[k] and R[k] for which I plotted these functions versus k. But now
> wants to see the effect of including a random function in the expression
> for S[k]. Daniel made suggestion that seem to work except that I was
> getting  some error message from his suggestion shown below. The error
> message is Do::itform: Argument R[k+1]=f S[k] R[k] at position 2 does
> not have the correct form for an iterator. >>. Will someone please help
> out. I spent hours in the Help pages of Mathematica, ver 6 without
> success. I am afraid to load ver 7 as of now.

<snip>

Kale,

I have tried the code you posted and haven't get any error or warning 
messages (Mathematica 6.0.3 on 64-bit Mac OS X 10.5.6). However, both 
sequences converge swiftly towards zero.

B = 8.;

f = 3. 10^-5;

n = 10;

S[0] = 3400;

R[0] = 9;

Do[S[k + 1] = R[k]*B Random[] - f*S[k]*R[k];
  R[k + 1] = f*S[k]*R[k];, {k, 0, 10}]

?S

Global`S

S[0]=3400

S[1]=50.7733

S[2]=3.17097

S[3]=0.00512872

S[4]=7.01914*10^-7

S[5]=1.56343*10^-13

S[6]=1.15181*10^-24

S[7]=5.86043*10^-42

S[8]=9.93852*10^-71

S[9]=3.9327*10^-116

S[10]=1.48464*10^-190

S[11]=7.525530556855338*10^-311


?R

Global`R

R[0]=9

R[1]=0.918

R[2]=0.0013983

R[3]=1.33019*10^-7

R[4]=2.04665*10^-14

R[5]=4.30971*10^-25

R[6]=2.02138*10^-42

R[7]=6.98472*10^-71

R[8]=1.228*10^-116

R[9]=3.66136*10^-191

R[10]=4.319715040784381*10^-311

R[11]=1.923966547814739*10^-505


Regards,
-- Jean-Marc

• References:
  • Re: Need Help
    • From: Bill Rowe <readnews@sbcglobal.net>