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Groups > comp.soft-sys.math.maple > #1026

Re: Vectors in the Physics package

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rouben@shadow.(none) (Rouben Rostamian) writes:

> This is a question about Physics[Vectors] package.
>
> Let's say we want to plot the helix v = [ cos(t), sin((t), t], where
> v is given as a Physics Vector.  Here is what I do:
>
>     restart;
>     with(Physics[Vectors]):
>     Setup(mathematicalnotation=true):
>     with(plots):
>     v_ := cos(t)*_i + sin(t)*_j + t*_k;
>     spacecurve( [ Component(v_,1), Component(v_,2), Component(v_,3) ],
>        t=0..4*Pi);
>
> This works fine, but the extraction of the components in the last
> line looks too clunky to me.  Alternatively we may do
>
>     spacecurve( [ v_ . _i, v_ . _j, v_ . _k ], t=0..4*Pi);
>
> which is a bit shorter, but I suspect that I am missing something
> more basic.  I tried convert(v_, list) and convert(v_, Vector)
> but did not get anything useful.
>
> So the question is one of:
> a) Is there a command to convert v_ to a list or a Vector?
> b) Is there some other way to plot the spacecurve given by v_?

You could do

  basis := [_i,_j,_k]:

then

  spacecurve( v_.basis, t=0..4*Pi);

does what you want.

-- 
Joe Riel

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Thread

Vectors in the Physics package rouben@shadow.(none) (Rouben Rostamian) - 2014-11-13 17:34 +0000
  Re: Vectors in the Physics package Joe Riel <joer@san.rr.com> - 2014-11-13 11:09 -0800
    Re: Vectors in the Physics package rouben@shadow.(none) (Rouben Rostamian) - 2014-11-14 08:11 +0000
      Re: Vectors in the Physics package rouben@shadow.(none) (Rouben Rostamian) - 2014-11-14 08:27 +0000
        Re: Vectors in the Physics package Joe Riel <joer@san.rr.com> - 2014-11-14 07:38 -0800
          Re: Vectors in the Physics package rouben@shadow.(none) (Rouben Rostamian) - 2014-11-15 05:41 +0000
            Re: Vectors in the Physics package Joe Riel <joer@san.rr.com> - 2014-11-15 08:22 -0800

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