[sage-support] Re: beginner problems
On 20 Dub, 08:17, Florian Beutler florian.beut...@gmx.de wrote: if I use rho = 0.0058/((r/2.4)*(1+(r/2.4))^2) integral(rho,r,0,10) btw: your integral is divergent (behaves like 1/r near zero). R. --~--~-~--~~~---~--~~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~--~~~~--~~--~--~---
[sage-support] Re: beginner problems
Hi, try this
r=var('r')
rho = 0.0058/((r/2.4)*(1+(r/2.4))^2)
integral(rho,r,0.01,10).n()
Robert Marik
On 20 Dub, 08:17, Florian Beutler florian.beut...@gmx.de wrote:
hallo
I just installed sage today and probably the problem I have at the
moment is a typical beginner problem, but unfortunately the tutorial
was not helpful concerning this points.
I am very in favor for sage, especially because it is written in
python but I think I need a somehow better (more details) tutorial.
Can anybody link me to another one (I read the tutorial provided on
the sage webpage)?
I define a equation which I would like to integrate... I simplified
the equation to reduce the possible errors
if I use
rho = 0.0058/((r/2.4)*(1+(r/2.4))^2)
integral(rho,r,0,10)
this does not work because for r=0 rho is not defined. But anyway I
want to integrate over the complete radius. What do I have to do?
I can avoid the problem by using
integral(rho,r,0.01,10)
this gives:
0.01392*(10.6953303525 - (125003*log(500012) - 125003*log(10) - 3)/
125003)
how is it possible to force sage to give me one value and not this
helpless term above?
thanks
regards
florian
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[sage-support] Re: beginner problems
hi Florian
Florian Beutler wrote:
hallo
I just installed sage today and probably the problem I have at the
moment is a typical beginner problem, but unfortunately the tutorial
was not helpful concerning this points.
I was in the same situation 3 weeks ago. I have the same feeling with
the manual, and as soon as I get a little bit more familiar with Sage
and the programming/documentation I will try to make some contributions
to the manual. I would recommend you 2 things.
1.- Take a look to Sage For Newbies. Google it, its for free and it
takes approximately 20 min to read the guide and become familiar with
the easy things of Sage.
2.- Log in into the Sage database (sagenb.org) and have a look to the
literally thousands of worksheets there. Many people (included myself)
leave its guides and ways to solve certain task with Sage.
if I use
rho = 0.0058/((r/2.4)*(1+(r/2.4))^2)
integral(rho,r,0,10)
this does not work because for r=0 rho is not defined. But anyway I
want to integrate over the complete radius. What do I have to do?
I can avoid the problem by using
Use the following to define r as symbolic variable
r=var('r')
rho = 0.0058/((r/2.4)*(1+(r/2.4))^2
and solve the integral numerically with the n() method (see The Sage
Tutorial page 6)
sage: integral(rho,r,1E-5,1E5).n()
0.158526563291981
integral(rho,r,0.01,10)
this gives:
0.01392*(10.6953303525 - (125003*log(500012) - 125003*log(10) - 3)/
125003)
how is it possible to force sage to give me one value and not this
helpless term above?
thanks
regards
florian
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