Re: integral

[Miroslaw Kwasniak]

On Thu, Aug 18, 2005 at 09:56:07PM -0700, Fred J. wrote:
> Hello
> 
> I need to do an integration
> 
> integrate_0^(x-1/2) integrate_(1/2+y)^0 12xy(1-y) dx
> dy
> 
> how can I use octave to do this. I have been reading a
> lot in the
> first few pages of the manual but need to know if this
> is even do-able
> with octave?

Octave doesn't have symbolic toolbox but you can use Maxima.
See my (very, very) simple function for calling Maxima (with bash shell):

$ cat /tmp/Maxima.m
function Y = Maxima (X)
  x = [ "tmp=/tmp/$$.tmp;" ...
        "echo 'display2d:false$", X, ";'" ...
        "|maxima|tee \"$tmp\"|grep o2|" ...
         "(" ...
             "read x  y;" ...
             "[ -n \"$y\" ]&&echo \"$y\"||((echo ERROR;cat \"$tmp\") >&2)" ...
         ");rm \"$tmp\""];
  Y = system (x);
endfunction

octave:67> exp0="integrate(integrate(12*x*y*(1-y),x,1/2+y,0),y,0,x-1/2)";
octave:68> exp1=Maxima(exp0)
exp1 = 3*(32*x^5-80*x^4+40*x^3-1)/80



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