Vector divide with negative ratio?

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SUMMARY

The discussion centers on finding the position vector of point P, which divides the line segment AB in the ratio 5:-2, with points A (-1, 6, 4) and B (4, 1, -1). The participants express confusion regarding the interpretation of negative ratios in vector division and clarify that the notation 'P divides AB in the ratio r:s' implies the relationship $$\frac{\vec{AP}}{r}=\frac{\vec{PB}}{s}$$. The negative ratio indicates that point P is positioned outside the segment AB, leading to further inquiries about the implications of such terminology in vector mathematics.

PREREQUISITES
  • Understanding of vector notation and operations
  • Familiarity with the Ratio Theorem in vector mathematics
  • Basic knowledge of coordinate geometry
  • Ability to manipulate ratios and proportions in mathematical contexts
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  • Study the Ratio Theorem in vector mathematics
  • Learn how to calculate position vectors using the section formula
  • Explore the implications of negative ratios in vector division
  • Review examples of vector division in coordinate geometry
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terryds
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Homework Statement


[/B]
Find the position vector of point P if P divides AB in the ratio 5:-2 given A (-1,6,4) and B (4,1,-1)

The Attempt at a Solution



The only trouble I have is to understand the question...

Does it mean something like

A------------------>B<----------------------P
3 2

Or

A----------------->P<-----------------------B
5 2Please help
 
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What strange terminology! I've not seen anybody use ratios with vectors that way before.
I can only guess that when they say 'P divides AB in the ratio r:s' they mean
$$\frac{\vec{AP}}{r}=\frac{\vec{PB}}{s}$$

Which of your two options does that favour?
 
andrewkirk said:
What strange terminology! I've not seen anybody use ratios with vectors that way before.
I can only guess that when they say 'P divides AB in the ratio r:s' they mean
$$\frac{\vec{AP}}{r}=\frac{\vec{PB}}{s}$$

Which of your two options does that favour?

Hmm... I just don't understand what the negative sign means...
Is it really strange to use ratio with vectors? It's on the subchapter "Ratio Theorem" in Vector chapter.
 

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