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Re: what am I doing wrong? [message #3586] Fri, 17 February 1995 13:50
jeyadev is currently offline  jeyadev
Messages: 78
Registered: February 1995
Member
In article <3i0pg0$rf@atom.ansto.gov.au>,
Babak Ardekani <babaka@atom.ansto.gov.au> wrote:
> Dear Netters,
>
> I'm trying to plot the funtion:
>
> f(x)=x*log(x/w)-x (x>0,w>0)
>
> using PV~WAVE.
>
> I know that this function has a minimum at x=w.
>
> ............
>
> THE PROBLEM IS that when I plot this function in PV~WAVE
> the minimum appears at another point.
>
> I'm using the following set of commands:
>
> WAVE> w=5.0
> WAVE> x=INDGEN(400)
> WAVE> x=x+0.1 + 0.01 ; x goes from 0.01 to 40.01
> WAVE> fx=x*ALOG10(x/w)-x
^^

That's what is wrong. Use ALOG(x/w) - the natural logrithm.

> WAVE> PLOT,x,fx
>
> I would appreciate if you would tell me what I'm doing
> wrong?
Re: what am I doing wrong? [message #3598 is a reply to message #3586] Thu, 16 February 1995 23:09 Go to previous message
babaka is currently offline  babaka
Messages: 3
Registered: February 1995
Junior Member
Please ignore this topic, as I have realized what the
problem was.

--
Babak A. Ardekani babaka@atom.ansto.gov.au
Dept. of Nuclear Medicine phone: +61-2-516-8011
Royal Prince Alfred Hospital fax: +61-2-550-5172
Missinden Rd., Camperdown, NSW 2050 AUSTRALIA
Re: what am I doing wrong? [message #3601 is a reply to message #3598] Thu, 16 February 1995 16:27 Go to previous message
babaka is currently offline  babaka
Messages: 3
Registered: February 1995
Junior Member
This is a correcton to my last posting. The line

> WAVE> x=x+0.1 + 0.01 ; x goes from 0.01 to 40.01

should really be:

WAVE> x=x*0.1 + 0.01 ; x goes from 0.01 to 40.01

This was a typo. The problem still remains.


--
Babak A. Ardekani babaka@atom.ansto.gov.au
Dept. of Nuclear Medicine phone: +61-2-516-8011
Royal Prince Alfred Hospital fax: +61-2-550-5172
Missinden Rd., Camperdown, NSW 2050 AUSTRALIA
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