the original was actually sqrt(2*x - 3) == 2 + sqrt(x+7) if that makes a difference... hmmm
On Jan 21, 1:14 pm, Marshall Hampton <[email protected]> wrote: > x=2 is not a solution of your original system. When you solved by > hand, presumably you squared things to eliminate the square root, but > that introduced the spurious solution x=2. > > The solve command uses maxima currently, and I don't know exactly how > it does things. Perhaps someone else can comment. For polynomial > systems such solvers usually fall back on Groebner bases. Since your > equation isn't in polynomial form, I think a symbolic solver would > have to convert it into such a form, and then somehow check the > answers in a form equivalent to the original. That seems hard but > perhaps its been done for equations with square roots, or maybe there > are other techniques. > > To get numerical solutions you can use the find_root command, and > perhaps check an exact form using algdep. > > Hope that helps, > Marshall Hampton > > On Jan 21, 12:14 am, Skylar <[email protected]> wrote: > > > I worked it out by hand to be x=2 or x=42. I get nothing useful back > > from sage. What am I missing? --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
