HelpGiven a common intersection point, create 3 different planes

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Homework Help Overview

The problem involves finding three different planes that intersect at a common point (3,4,5). The context is within a calculus framework, specifically relating to the concept of planes in three-dimensional space.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • The original poster attempts to express the planes in terms of linear equations but encounters difficulties with the unknowns. Another participant suggests simple equations for the planes based on the intersection point. There is a discussion about justifying the intersection point using Cramer's rule and vector operations.

Discussion Status

The discussion is active, with participants exploring different methods to define the planes and validate the intersection point. There is no explicit consensus, but various approaches are being considered, including direct equations and determinant calculations.

Contextual Notes

The original poster mentions a lack of algebra background, which may influence their understanding of the problem. There is also a reference to the conditions for using Cramer's rule, specifically the requirement that the determinant is not equal to zero.

silentfire
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Homework Statement


Given a common intersection point (3,4,5), find 3 different planes.


Homework Equations


None


The Attempt at a Solution



What I did is let

a1x+a2y+a3z=a
b1x+b2y+b3z=b
c1x+c2y+c3z=c

3=Dx/D 4=Dy/D 5=Dz/D

I set D=2, therefore Dx=6 Dy=8 Dz=10,
I was stuck then, no matter how I did I just got a bunch of unknown.
This question is supposed to find any 3 linear equations(aka 3 planes) that satisfy the intersection point.

Well, who doesn't know how to find the intersecting point using Cramer's rule...

P/S: This question comes up in my calculus 3 question, and I have not taken any algebra course yet, so I only know the condition for Cramer's rule for a common intersection point to take place which is D not equal to 0.
 
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If you want 3 different planes that intersect at (3,4,5), why not just use z=5, y=4, and x=3?
 
Thanks a lot dustin for your reply.

If i want to justify that this is indeed the intersection point of the 3 different planes you mentioned, can I apply Cramer's rule and then do the dot and cross products with the normal vectors of the 3 planes. If the determinant is indeed not equal to 0, then the intersection point is justified?
 
Well if we use those equations then are we would have x+0y+0z=3; 0x+y+0z=4; 0x+0y+z=5. Which would make our determinant 1.
 

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