On Jan 16, 2008 3:11 PM, Jason Grout <[EMAIL PROTECTED]> wrote: > > > David Joyner wrote: > > Hi: > > > > I don't remember this topic coming up before but at some point > > it must be faced since it arises in Calculus 1. AFAIK, SAGE has no routines > > for > > (1) computing the "implicit derivative" y' if y is defined implicitly > > by F(x,y)=0, > > (2) plotting (x,y) subject to F(x,y)=0. > > > > (1): This is easy for SAGE to compute: y' = - F_x(x,y)/F_y(x,y). > > The problem is that it just isn't implemented yet to my knowledge. > > How should this be implemented? implicit_derivative(F(x,y),x) or something?? > > Suggestions? > > > > (2) In the 2d case, it might be possible to tweek matplotlib's > > contourplot. It might also be possible to plot the solution to > > the 1st order DE y' = - F_x(x,y)/F_y(x,y). Suggestions? > > > It appears that Maxima has an implicit_plot command: > > http://maxima.sourceforge.net/docs/manual/en/maxima_55.html > > The example seems to work for me with sage -maxima.
That calls gnuplot though. The option [plot_format,openmath] (which calls the open source tk/tcl plotter openmath) seems not to be allowed for implicit_plot. > > Jason > > > > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://sage.scipy.org/sage/ and http://modular.math.washington.edu/sage/ -~----------~----~----~----~------~----~------~--~---
