# Graph a 2-sphere on graphcalc

1. Jul 18, 2005

i attempted to graph a 2-sphere on graphcalc and it wouldn't work. the equations had to be in terms of z, so i had to use: $$z=\sqrt{-x^2-y^2+9}$$ and $$z=-\sqrt{-x^2-y^2+9}$$. i thought that would give me a 2-sphere at the origin with a radius of 3, but it didn't. i got:[PLAIN]http://photobucket.com/albums/a192/YoDizzle/th_almostsphere.bmp.[/URL] [Broken] what did i do wrong?