# Thread: mathematica 7 :plot3d: plz help

1. ## mathematica 7 :plot3d: plz help

hi

how can i draw ( X^2+(Z-0.5)^2== 1 ) by using plot3d in mathematica 7

2. Originally Posted by acied
hi

how can i draw ( X^2+(Z-0.5)^2== 1 ) by using plot3d in mathematica 7
I have not had luck plotting non-functions in Mathematica. I would solve for z, resulting in

$\displaystyle z=\sqrt{1-x^2}+\frac{1}{2}$

OR

$\displaystyle z=-\sqrt{1-x^2}+\frac{1}{2}$

Then inputting

Code:
Plot3D[{Sqrt[1 - x^2] + 1/2, -Sqrt[1 - x^2] + 1/2}, {x, -10, 10}, {y, -10, 10}]

3. Or you could try a ParametricPlot3D command.

4. Isn't that just a circle in the xz-plane?

Code:
ContourPlot[x^2 + (z - .5)^2 == 1, {x, -2, 2}, {z, -2, 2}]

5. Originally Posted by scorpion007
Isn't that just a circle in the xz-plane?
The surface is an infinitely long cylinder. The surface's intersection with the xz-plane is a circle.

6. Originally Posted by acied
hi

how can i draw ( X^2+(Z-0.5)^2== 1 ) by using plot3d in mathematica 7
ContourPlot3D[x^2+(z-0.5)^2==1,{x,-5,5},{y,-5,5},{z,-5,5}]