Dot product, i don't see what they want from me

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Homework Help Overview

The discussion revolves around understanding the dot product of vectors and identifying a family of vectors that are perpendicular to a given vector in R^3. The original poster expresses confusion regarding the requirements of the problem, particularly in finding additional numbers for a parametric form.

Discussion Character

  • Exploratory, Conceptual clarification, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the condition for perpendicularity in terms of the dot product and explore how to express a family of vectors that satisfy this condition. Questions arise about the method for finding these vectors and the meaning of the parametric form.

Discussion Status

Some participants have provided guidance on how to approach the problem by suggesting the use of a general vector and setting up the dot product equation. There is an acknowledgment of the infinite solutions possible due to the presence of three variables and only one equation.

Contextual Notes

The original poster mentions a specific vector and the requirement for a parametric representation, indicating constraints in the problem setup that may affect the discussion.

mr_coffee
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hello everyone, i understand the dot product and its properties but i don't get what they want! They say...
The dot product of two vectors are perpendicular if a.b = 0.
Then any vector in R^3 perpendicular to

-5
-6
-3

note: that is a matrix above.

can be written in the form:
and it looks like parameteric forum they want, because they want a column of s and a column of t. but i don't see where I'm suppose to find more numbers.
 
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Call the vector you are given A, you need to find, and descripe the family of vectors (b) which satisfy the condition:

[tex]A \cdot b = 0[/tex]
 
thanks for the responce!
how do you find a family of vectors?
 
First, take anoter "general" vectors, let's say (x,y,z). Take the dot product with (-5,-6,-3) and let it equal 0.
Now you have 1 equation with 3 variables which has infinite many solutions. Solve it by choosing two variables (e.g. let x = s and y = t, then solve for z)
 
Awesome! thanks again TD, you should be getting paid for this hah. :-p
 
You're welcome :smile:
 

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