Re: Forcing a Fit through a Data Point (Mathematica 5)

• To: mathgroup at smc.vnet.net
• Subject: [mg43594] Re: Forcing a Fit through a Data Point (Mathematica 5)
• From: "Robert Nowak" <robert.nowak at ims.co.at>
• Date: Tue, 23 Sep 2003 04:01:37 -0400 (EDT)
• References: <bkm7pa\$rhj\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```hi,
just omit the constant term (that is the "1" in {1,x}) in your fit to get a
line through (0, 0)
abc = Fit[data, {x}, x]

by the way your original  Fit[data, {1, x, x}, x] hase one x to much in  {1,
x, x} but mathematica seems not to mind it.

regards robert

"Hank Shih" <airforce1 at comcast.net> wrote in message
news:bkm7pa\$rhj\$1 at smc.vnet.net...
> Hello all. I have a set of data for a experiment and I want to create
> the best fit line. Based on the x-y coordinate system, I need the line
> to go through (0, 0) no matter what. The data is as followed: data =
> {{0,0}, {.5,.25}, {1,.4}, {1.5,.5}, {2,.625}, {2.5,.84615}, {3,1},
> {3.5,1.0588}}.
>
>
> data = {{0,0}, {.5,.25}, {1,.4}, {1.5,.5}, {2,.625}, {2.5,.84615},
> {3,1}, {3.5,1.0588}}.
>
> abc = Fit[data, {1, x, x}, x]
> Plot[abc, {x, 0, 5}, GridLines -> Automatic, AxesLabel -> {"Time (in
>        sec)", "Change in Distance (in cm)"},
>    Epilog -> {PointSize[0.02], Map[Point, data]}]
>
> Is there a easier way to do this through Mathematica 5? If not, how can
> I force it through that (0, 0) point? Thanks in advance
>
> Hank
>

```

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