Re: Newbie Plot-Fit Questions.
- To: mathgroup at smc.vnet.net
- Subject: [mg31126] Re: Newbie Plot-Fit Questions.
- From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
- Date: Fri, 12 Oct 2001 03:36:43 -0400 (EDT)
- Organization: Universitaet Leipzig
- References: <9q2l22$p4d$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Hi,
Plot[] has the attribute HoldAll and you have to enclose
an argument by Evaluate[] if you wish to evaluate it and
Plot[Evaluate[(Fit[{{2942, 3650782}, {2955, 2255796}, {3204, 730421},
{4105,
1740135}, {7815, 6329111}, {13097, 7116844}}, {1, x, x^2,
x^3},
x])], {x, 2942, 13097}]
work as expected.
Regards
Jens
SkyBeaux wrote:
>
> Please explain this to me:
>
> If I do the following:
>
> Fit[{{2942, 3650782}, {2955, 2255796}, {3204, 730421}, {4105,
> 1740135}, {7815,
> 6329111}, {13097, 7116844}}, {1, x, x^2, x^3}, x]
>
> Results are:
> \!\(1.7044496230729986`*^7 - 8507.38287339198`\ x +
> 1.3901134594316935`\ x\^2 - 0.00006096360495406324`\ x\^3\)
>
> Then I plot the results as follows:
>
> \!\(Plot[1.7044496230729986`*^7 - 8507.38287339198`\ x +
> 1.3901134594316935`\ x\^2 - 0.00006096360495406324`\ x\^3, {x,
> 2942,
> 13097}]\)
>
> I get a nice "sin" looking plot. (This is what I want.)
>
> However if I try to combine the two statements into one. Like this:
>
> Plot[(Fit[{{2942, 3650782}, {2955, 2255796}, {3204, 730421}, {4105,
> 1740135}, {7815, 6329111}, {13097, 7116844}}, {1, x, x^2,
> x^3},
> x]), {x, 2942, 13097}]
>
> I get a linear chart.
>
> What is the difference? And how do I get my nice "sin" looking plot
> back?
>
> As you can see, I an not really sure what is being plotted by the
> first set of commands, but I think it is a log plot.
>
> Thanks for you help.
>
> --SB