Solve Nested Ball Problem: r_big-r_small ≤ d(x,y)

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In summary, the conversation discusses a problem involving proving that the distance between the centers of two nested balls is less than the difference in their radii. The proposed solution involves using the triangle inequality and considering the containment of the smaller circle within the larger one.
  • #1
robertdeniro
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Homework Statement


given a ball within another ball
show that the distances between their centers are less than the difference in their radii

Homework Equations





The Attempt at a Solution


let r_big and r_small represent the respective radii and let x and y represent the centers of the big and small balls

i got d(x,y)<=r_big+r_small by triangle inequality but i need r_big-r_small
 
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  • #2
Did you try and draw two circles in the plane where |x-y|>r_big-r_small and try to figure out why the smaller circle can't be contained in the larger circle? If you can explain that in words, then you are probably halfway there.
 
  • #3
nm i got it
 
Last edited:

1. What is the "Nested Ball Problem"?

The Nested Ball Problem is a mathematical concept that involves finding the maximum number of nested balls that can fit inside a larger ball, given a specific radius difference between the two balls. This problem has numerous applications in geometry, topology, and optimization.

2. What is the significance of the "r_big-r_small ≤ d(x,y)" condition in the Nested Ball Problem?

The condition r_big-r_small ≤ d(x,y) ensures that the nested balls are all touching each other and the outer ball, without any gaps or overlaps. This ensures that the balls are fit snugly inside the larger ball, maximizing the number of nested balls that can fit.

3. How is the Nested Ball Problem solved?

The Nested Ball Problem can be solved using various mathematical techniques, such as geometric reasoning, calculus, and optimization algorithms. The specific approach used may vary depending on the given parameters and the desired outcome.

4. What are some real-life applications of the Nested Ball Problem?

The Nested Ball Problem has various real-life applications, including packing problems in manufacturing industries, optimization of storage space in warehouses, and even the design of efficient packaging for transportation of goods.

5. Are there any other variations of the Nested Ball Problem?

Yes, there are several variations of the Nested Ball Problem, such as the Multi-dimensional Nested Ball Problem, where the balls exist in higher dimensions, and the Discrete Nested Ball Problem, where the balls have discrete sizes. Each variation has its own set of challenges and applications.

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