Finding the Center and Radius of a Sphere: A Homework Question

In summary, the conversation discusses finding the center and radius of a sphere represented by the equation 16x^2+16y^2+16z^2-96x+32y=5. The solution involves completing the square and adjusting the right side of the equation. The correct center is (3,-1,0) and the radius is not (15^.5)/4.
  • #1
bobbarkernar
48
0

Homework Statement



The equation represents a sphere.

16x^2+16y^2+16z^2-96x+32y=5

Find its center, and radius



Homework Equations





The Attempt at a Solution


i found the center by completing the square:

16[(x^2-6x+9)+(y^2+2y+1)+(z^2)]=5+9+1
16[(x-3)^2 +(y+1)^2 +(z+0)^2]=15

the center is (3,-1,0)
i thought the radius would be (15^.5)/4 but that was incorrect if someone could please help me thank you
 
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  • #2
bobbarkernar said:

Homework Statement



16[(x^2-6x+9)+(y^2+2y+1)+(z^2)]=5+9+1
16[(x-3)^2 +(y+1)^2 +(z+0)^2]=15

You forgot to multiply the added 1 and 9 on the right side by 16. Either multiply everything out on the left side and see what needs to be added to equalize the right side or try going back and dividing everything by 16 before completing the square.
 
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  • #3
ok i see what i did wrong. thank you very much
 

What is the center of a sphere?

The center of a sphere is the point that is equidistant from all points on the surface of the sphere. It is often denoted by the letter "O" or sometimes "C".

How is the center of a sphere determined?

The center of a sphere can be determined by finding the midpoint of any diameter of the sphere. This can be done by measuring the distance between any two points on the sphere's surface and then dividing that distance by two. The resulting point will be the center of the sphere.

What is the radius of a sphere?

The radius of a sphere is the distance from the center of the sphere to any point on its surface. It is denoted by the letter "r".

How is the radius of a sphere calculated?

The radius of a sphere can be calculated using the formula r = d/2, where d is the length of any diameter of the sphere. It can also be calculated by finding the square root of the sphere's volume divided by 4π.

What is the relationship between the center and radius of a sphere?

The center and radius of a sphere are closely related, as the radius is the distance from the center to any point on the sphere's surface. In fact, the center and radius are the two key components used to define a sphere.

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