Can the distance between a point and a line segment be minimized?

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SUMMARY

The discussion centers on minimizing the distance between a point P and a line segment L defined by the equation y=3x+1 with endpoints (2, 7) and (6, 19). The extreme value theorem is highlighted as a key concept, indicating that a continuous function on a compact set achieves its extreme values. Two cases are presented: if point P lies between the normals drawn from the endpoints, the minimum distance is along the normal; if P lies outside, the minimum distance is to the nearest endpoint of the segment.

PREREQUISITES
  • Understanding of the extreme value theorem in calculus
  • Familiarity with line equations and slopes
  • Knowledge of geometric concepts involving distance minimization
  • Ability to analyze regions defined by lines in a plane
NEXT STEPS
  • Study the extreme value theorem in more depth
  • Learn about geometric interpretations of distance in coordinate systems
  • Explore methods for finding distances from points to lines and line segments
  • Investigate the properties of normal lines in geometry
USEFUL FOR

Students studying calculus, geometry enthusiasts, and anyone interested in optimization problems involving distances in a coordinate plane.

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Homework Statement


Let L be the segment of the Line y=3x+1 with end points (2, 7) and (6, 19).

If P is a point not on L, is it guaranteed that the distance between P and L can be Minimized?


Homework Equations



None Really.


The Attempt at a Solution



I looked through my book but couldn't really find anything that was directly related to this. Is there some kind of famous theorem or something that should be obvious?
 
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Hi Cina,

Are you familiar with the extreme value theorem in terms of compact sets? It says that a continuous, real-valued function defined on a compact set attains its extreme values.
 
The slope of the given line is -1/3. Draw a line with this slope through each endpoint of the line segment. These two normal lines divide the plane into three regions.

Case 1: If P lies between the two normals that were drawn, the minimum distance from the given line to P is the length along the normal from the given line to P.

Case 2: If P lies outside of the two lines, the minimum distance from P to the line is the distance between P and the closer of the two endpoints.
 

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