Vector Addition and Subtraction in Three Dimensions

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Homework Help Overview

The discussion revolves around finding the position vector of point D in a parallelogram formed by points A, B, and C in three-dimensional space. The problem involves vector addition and subtraction.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the use of vector equations and the relationships between the points. Some express confusion about the correctness of their equations and the relevance of unit vectors and norms in this context.

Discussion Status

There is an ongoing exploration of the correct approach to the problem, with some participants suggesting that vector addition and subtraction are the key operations needed. Others are questioning their previous methods and assumptions.

Contextual Notes

Participants are navigating through potential errors in their calculations and assumptions, particularly regarding the use of norms and unit vectors, which may not be necessary for this problem.

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Homework Statement



Point A (2i +j 2k)
Point B (3i +2j +5k)
Point C (4i +5j -2k)

the point d is such that abcd in that order is a parallelogram.

Find position Vector D


Homework Equations





The Attempt at a Solution



ok so i start of like this but I am getting the wrong answer.
http://img511.imageshack.us/img511/5946/vectorak5.jpg

(BA)^1/2=(CD)^1/2

but its wrong.
 
Last edited by a moderator:
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It might be useful to make a drawing.
 
Yes, but are those equations correct
I've realized my error.
culd you tell me the point of the unit vector.
 
Last edited:
You don't need to do anything involving norms or unit vectors here, so the square root stuff is way off base. It's really just a matter of vector addition, and subtraction.

\vec{BA}=\vec{OD} - \vec {OC}
makes sense to me, the other equations don't really.
 

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