<p>Is it possible to graph spheres on this? I have no idea what the equation would be</p>
<p>The equation of a sphere is x^2 + y^2 + z^2 = r^2
As to whether you can graph it on an 89, I have no clue.</p>
<p>EDIT: I got something to happen lol.</p>
<p>Go to mode and under graph it should say "Function". Change is to "3D" and press enter.
Then go to "Y=". It should say z=(blank). Type in sqrt(-x^2-y^2+25) for z1 and -sqrt(-x^2-y^2+25) for z2
It didn't turn out too well, but you can mess around with that.</p>
<p>Yep. The equation for a sphere with center (h,k,l) and radius r is:</p>
<p>(x-h)^2 + (y-k)^2 + (z-l)^2 = r^2</p>
<p>yeah you can do it on ti89</p>