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