Re: rules->function:THANKS+new plotting question

*To*: mathgroup at smc.vnet.net*Subject*: [mg7393] Re: rules->function:THANKS+new plotting question*From*: Lord of Darkness <j.biddiscombe at rl.ac.uk>*Date*: Fri, 30 May 1997 01:19:55 -0400 (EDT)*Organization*: Rutherford Appleton Laboratory*Sender*: owner-wri-mathgroup at wolfram.com

Thanks to all the people who replied to my rules->function question it turns out the problem was being caused by... soln=Solve[equation,z] gave out[...]: {{z->blah blah...}} and it was the presence of the curly brackets that was the problem. If I put f[x_,y_] := Replace[Flatten[soln][[n]]]] (n = solution number for multiple solutions) then the problem goes away. --------------------------- Here's a new question If I wish to plot a function say f[x,y] {x,xmin,xmax},{y,ymin,ymax} then the range of values is effectively a rectangular region in (x,y) But.. Suppose values of y do not exist for all values of x, and I wish to plot ParametricPlot[f[x,y],{x,xmin,xmax},{y,ymin[x],ymax[x]}] so the values of y are dependent on x - ie my solution space is no longer a regtangular region, but some arbitrary shape depending on ymin[] and ymax[] How do I do that ? Help gratefully appreciated.. John B