Nullcline and getting "2" values for y

*To*: mathgroup at smc.vnet.net*Subject*: [mg81468] Nullcline and getting "2" values for y*From*: sean_incali <sean_incali at yahoo.com>*Date*: Mon, 24 Sep 2007 04:21:14 -0400 (EDT)

I have this equation I can plot using the following ClearAll["Global`*"] fun = (b c y - a y^ n + y^(1 + n))/(b + y^n); d = 0.1; c = 1; b = 10; a = 11; n = 5; ParametricPlot[{fun, (y)}, {y, 0, 1}, PlotRange -> All] I am plotting the function "fun" against values of y. When I do that I get a curvew that clearly shows that, for a given value of y, I should get two value for the function. How do I get what they are? If I just go.. d = 0.1; c = 1; b = 10; a = 11; n = 2; y = 0.5; (b c y - a y^ n + y^(1 + n))/(b + y^n) I get 0.231707 but starting at y=0 all the way to y= 0.6 or so, there are two values! (according to the graph) How do I get what those values are? Thanks for any input. sean