Re: ContourPlot confusion

*To*: mathgroup at smc.vnet.net*Subject*: [mg116384] Re: ContourPlot confusion*From*: "Sjoerd C. de Vries" <sjoerd.c.devries at gmail.com>*Date*: Sat, 12 Feb 2011 05:21:28 -0500 (EST)*References*: <ij2ukh$7im$1@smc.vnet.net>

I suppose it should evaluate to 0. If it's a wildly changing function you may expect large values in the neighbourhood of this line. If you would disclose your function there might be more to say here. Cheers -- Sjoerd On Feb 11, 10:13 am, kelly <kere... at gmail.com> wrote: > Hi! I'm plotting the following: > > ContourPlot[Expression[50, x, y] == 0), {x, -15, -17}, {y, -0.7, -0.5}] > > So some previously defined expression which is a function of 50, x, and y. I've set it to only show the "Expression = 0" contour, which it does. > > However, when I use "Get Coordinates" to get the coordinates of a point along this contour line & plug those coordinates back into the expression, it evaluates to around -33. Shouldn't it evaluate to 0 if the point lies along the 0 contour? > > Any help is appreciated! So confused!