Re: Newbie: Rotataion2D use problem
- To: mathgroup at smc.vnet.net
- Subject: [mg66725] Re: Newbie: Rotataion2D use problem
- From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
- Date: Sat, 27 May 2006 21:03:50 -0400 (EDT)
- Organization: The Open University, Milton Keynes, UK
- References: <e591hh$35m$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
akil wrote:
> I have some problems using Mathematica's Rotate2D, it doesnot give the results as I want them
>
> Eample:
>
> a={10, 30}
> b={80., 0.}
> c={38.7689, 0.}
> theta = -0.24497866312686414`
> theta2 = -0.3430239404207034`
> Rotate2D[a, theta, test[[1]]]
> Rotate2D[%, theta2, test[[2]]]
>
> this gives:
> \!\({2.7134309891835002`, 1.7763568394002505`*^-15}\)
>
> While the y-value should be 0 instead of 1.7763568394002505`*^-15.
>
> Anyone know how I can easily fix this, so that I get 0 here instead?
Hi Akil,
Use the built-in function *Chop* [1]: "Chop[expr] replaces approximate
real numbers in expr that are close to zero by the exact integer 0."
In[2]:=
Chop /@ {2.7134309891835002, 1.7763568394002505*^-15}
Out[2]=
{2.71343, 0}
Best regards,
Jean-Marc
[1] http://documents.wolfram.com/mathematica/functions/Chop