Re: y-axis direction

*To*: mathgroup at smc.vnet.net*Subject*: [mg116556] Re: y-axis direction*From*: Helen Read <readhpr at gmail.com>*Date*: Sat, 19 Feb 2011 05:15:07 -0500 (EST)*References*: <ijisli$27u$1@smc.vnet.net> <ijlek0$r5b$1@smc.vnet.net>

On 2/18/2011 4:37 AM, telefunkenvf14 wrote: > On Feb 17, 4:18 am, "Rob Y. H. Chai"<yhc... at ucdavis.edu> wrote: >> Hi all, >> >> In the Plot command, the convention for y-axis is up for positive values. Is >> there an easy way to reverse the y-axis direction i.e. pointing down for >> increasing positive y values? Thanks. >> >> Rob Chai > > I have encountered the same problem... economists like to graph > inverse demand and supply equations (i.e., price(quantity)) rather > than the true relationship of quantity(price). > > Possible ways around this: > > (1) solving for the inverse relationship and then using Plot[] (one > could also use InverseFunction[] ---- not always straightforward as > your function may not be clearly invertible w/o providing assumptions > on parameters) > (2) using ContourPlot[], which incorporates the functionality of the > legacy function ImplicitPlot (you can still use ImplicitPlot; search > documentation for details) > > For the most part, I've settled on (1). I think the OP is talking about something else, keeping the y-axis vertical but with reversed orientation on the y-axis (to which others have posted solutions). But for what you are talking about, I would suggest (3) ParametricPlot. That is, if you have x=f(y) make a ParametricPlot of {f[y],y} -- Helen Read University of Vermont