# Find an equation of the largest sphere with center...

Show 40 post(s) from this thread on one page
Page 1 of 2 12 Last
• Jan 21st 2011, 10:33 AM
thomann061
Find an equation of the largest sphere with center...
Find an equation of the largest sphere with center (11, 19 , 12) that is contained completely in the first octant.

Need help solving... thank you!
• Jan 21st 2011, 10:34 AM
dwsmith
Quote:

Originally Posted by thomann061
Find an equation of the largest sphere with center (11, 19 , 12) that is contained completely in the first octant.

Need help solving... thank you!

The coordinates give you the answer.
• Jan 21st 2011, 10:36 AM
thomann061
yes i know, i am confused about how to find the radius.
• Jan 21st 2011, 10:38 AM
dwsmith
Quote:

Originally Posted by thomann061
yes i know, i am confused about how to find the radius.

Have you plotted the center on a graph? If the radius is 19, is it possible for it not to exceed the 1st octant? What about 12?
• Jan 21st 2011, 10:51 AM
thomann061
yes i have graphed it. i came up with this as an answer so far: (x-11)^2 + (y-19)^2 + (z-12)^2 = 0. i dont know what you mean by if the radius is 19? i thought it would be around 2 or 4.
• Jan 21st 2011, 10:56 AM
dwsmith
Quote:

Originally Posted by thomann061
yes i have graphed it. i came up with this as an answer so far: (x-11)^2 + (y-19)^2 + (z-12)^2 = 0. i dont know what you mean by if the radius is 19? i thought it would be around 2 or 4.

You think a radius of 2 or 4 is the largest sphere you can fit in the first octant?

Also, your equation is of a point.
• Jan 21st 2011, 11:01 AM
thomann061
as you can tell i am very confused... i just can't seem to understand how to solve this or think about it visually. could you show me how to solve for it?
• Jan 21st 2011, 11:03 AM
dwsmith
Quote:

Originally Posted by thomann061
as you can tell i am very confused... i just can't seem to understand how to solve this or think about it visually. could you show me how to solve for it?

Draw a picture a find the center.
• Jan 21st 2011, 11:09 AM
thomann061
i found the center, i still cant tell how to find the radius
• Jan 21st 2011, 11:11 AM
dwsmith
Quote:

Originally Posted by thomann061
i found the center, i still cant tell how to find the radius

If you found the center, how far can you move away from it before you hit an axis: x, y, or z?
• Jan 21st 2011, 11:21 AM
thomann061
i mean 12 from the y axis
• Jan 21st 2011, 11:26 AM
dwsmith
Quote:

Originally Posted by thomann061
i mean 12 from the y axis

So if you move 12 units, you won't cross the x-axis?
• Jan 21st 2011, 11:26 AM
thomann061
ha i mean 19 from the x axis
• Jan 21st 2011, 11:34 AM
dwsmith
Quote:

Originally Posted by thomann061
ha i mean 19 from the x axis

Here is a sphere of 8 and 19. You tell me.

http://img339.imageshack.us/img339/8969/sphereex.jpg

http://img705.imageshack.us/img705/3388/61124892.jpg
• Jan 21st 2011, 11:37 AM
thomann061
ohhhh okay its 11^2 for the radius :)
Show 40 post(s) from this thread on one page
Page 1 of 2 12 Last