Hiya. Probably I have either done something wrong or this is a precision issue I should know about if I programmed. Please excuse. http://sagenb.org/home/pub/4706
I wanted to plot the level curves of a f(x,y,z)=sqrt(x^2-z) for C=0, 1, -1, 2, -2. So I typed in implicit_plot3d(sqrt(x^2-z)==0, (x,-2,2), (y,-5,5), (z,-4,4), opacity=.5) and nothing was graphed. I got no error message. After trying several changes, I gave up and did: implicit_plot3d(x^2-z==(0)^2, (x,-2,2), (y,-5,5), (z,-4,4), opacity=.5) and got my "elongated parabola" (published and sent off the reply). Now after experimenting I find that: C=1, C=2 are no problem. (GRAPH 2) In GRAPH 3, one can see: For C=0 no graph, C=.1 a tiny piece, C=.2 a couple of slivers, C=.3 a few more slivers and by C=.5 one gets the graph. BTW: I tried changing the z values (to make the argument always positive) to no effect. Question: Is there a way to know what graphs will plot and what won't? Thank-you for your help. Linda -- To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URL: http://www.sagemath.org
