Vector Equation Proof: Finding the Magnitude of a Vector Sum

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Homework Help Overview

The discussion revolves around proving a vector equation related to the magnitudes of vector sums and differences, specifically the expression llu+vll2 + llu-vll2 =2llull2 + 2llvll2. The subject area is vector mathematics, particularly focusing on properties of vector magnitudes and dot products.

Discussion Character

  • Exploratory, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the need to utilize dot products to find the lengths of vectors and explore the properties of these operations. There is uncertainty about how to initiate the proof, with some participants seeking clarification on the suggested approach.

Discussion Status

Some guidance has been provided regarding the use of the dot product to express the magnitudes of vectors. Participants are engaging with the suggestions, indicating a productive direction in the discussion.

Contextual Notes

There appears to be some confusion regarding the initial steps needed to approach the proof, with participants questioning the implications of the provided hints. The original poster expresses uncertainty about how to start the proof process.

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Homework Statement



Prove llu+vll2 + llu-vll2 =2llull2 + 2llvll2


Homework Equations



I am thinking I need to use some dot, or cross products.

The Attempt at a Solution



I just do not know where to start.
 
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Use what you know for finding the length of a vector (in terms of a dot product)and the associativity of the dot product.
 
What do you mean by that?
 
Baumer8993 said:
What do you mean by that?

||a||^2=a.a, use that.
 
Ohhh thanks! Now I get it.
 

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