Re: Crossing of 3D functions

*To*: mathgroup at smc.vnet.net*Subject*: [mg57005] Re: Crossing of 3D functions*From*: dh <dh at metrohm.ch>*Date*: Thu, 12 May 2005 02:33:05 -0400 (EDT)*Organization*: Cablecom Newsserver*References*: <d5sks6$o2t$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Hi Pawel, see below. Sincerely, Daniel Paawel wrote: > Hello > I have two functions of surfaces > > F1=\!\(\(-7.516\)*\ > Exp[\(-3.076\)*\((r - 1.184)\)]*\((1 - > 8.28*10\^\(-5\)*\((180\ - \ f)\)\^2)\)*0.7\^0.5 + > 3.758*Exp[\(-6.152\)*\((r - 1.184)\)] + 3.92\) > > and > > F2=\!\(\(-0.958\)*\ Exp[\(-4.993\)*\((r - 1.375)\)]*\((1 - \ > 1.07*10\^\(-3\)*\((133\ - \ f)\)\^2)\)*1\^0.5 + 0.479* > Exp[\(-9.986\)*\((r - 1.375)\)] + 0.479\) > > variables are r and f > > I want to find a plot which describes crossing of these functions. First load the package: Graphics`ImplicitPlot` Then the following will plot the crossing: ImplicitPlot[F1[r, f] == F2[r, f], {r, -1, 2}, AspectRatio -> 1/GoldenRatio] > > I tried Solve command but without any success > > I also tried a simpler example > Fa=Exp[-(x^2 + y^2)] > and > Fb=0.5 > and when I used > Solve[Fa == Fb, {y}] > I received y1 and y2 - two parts of wanted function > How to obtain one function (circle) from the above Fa nad Fb? The circle has two branches,one above the x-axis, the other below. Therefore it is not possible to specify y[x] as a single valued function of x, you have to live with two functions. > > Please Help > Pawel >