Re: Plotting a Vertical Line
- To: mathgroup@smc.vnet.net
- Subject: [mg11675] Re: [mg11606] Plotting a Vertical Line
- From: Sean Ross <seanross@worldnet.att.net>
- Date: Sat, 21 Mar 1998 18:35:12 -0500
- References: <199803200048.TAA05577@smc.vnet.net.>
Frank Roescher wrote:
>
> How do I get Mathematica to plot the graph of x = 3, i.e., a vertical
> line in 2D? Thanks.
The question is do you just want a vertical line on a graph or do you
actually want a multiple valued function? If you just want a vertical
line on a graph ,then do something like:
Show[Plot[0,{x,0,5}],Graphics[Line[{{3,-1},{3,1}}]]]
I don't know how to reliably plot a vertical line as a mathematical form
because of the problems in defining such a function in a way that Plot
will always make a nice graph. Consider, for example,
f[x]=If[x==3,1,0]. This is a function equal to 1 at x=3 and zero
elsewhere. The first problem is that this is not the same as the
"function" x=3 because x=3 is infinitely multiple valued. In any
event, the function f[x] will not display properly because Plot always
samples its functions at some interval and will not detect an
infinitely thin function and skip right over it.
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