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Re: Exclusions inconsistancy

• To: mathgroup at smc.vnet.net
• Subject: [mg79727] Re: Exclusions inconsistancy
• From: "David Park" <djmpark at comcast.net>
• Date: Thu, 2 Aug 2007 04:02:55 -0400 (EDT)
• References: <f8pj9l$269$1@smc.vnet.net>

The documentation doesn't say that Exclusions and ExclusionsStyle plots 
asymptotes. It only plots excluded regions. In the odd cases you cite the 
excluded region defines a line but in the even cases it only defines a point 
at infinity.

It would be nice to know the actual algorithm used, especially for 
2-dimensional exclusion regions. For the plots you cite it probably draws a 
line between the left and right limits.

-- 
David Park
djmpark at comcast.net
http://home.comcast.net/~djmpark/


"Ken Levasseur" <klevasseur at mac.com> wrote in message 
news:f8pj9l$269$1 at smc.vnet.net...
>A student just pointed out to me that the asymptote at x=1 is drawn
> in the following plot only when k is odd.  For even values, no
> asymptote appears.
>
> Plot[1/(x - 1)^k, {x, -5, 5}, PlotRange -> {{-5, 5}, {-5, 5}},
>    Exclusions -> {x - 1 == 0}, ExclusionsStyle -> {{Thick, Red}}]
>
> This appears to generalize to other examples like Tan[x]^k.
>
> Anyone know why?
>
> Ken Levasseur
> Mathematical Sciences
> UMass Lowell
>