Find Line in Plane Passing Through (2,3,6)

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Homework Help Overview

The problem involves finding a line in a given plane described by the equation 3x + 2y - z = 6 that passes through the point (2, 3, 6).

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the use of the normal vector to the plane and its relevance to finding a line within the plane. There is a suggestion to identify another point in the plane to determine the line.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem. Some guidance has been offered regarding the necessity of finding a second point in the plane, but there is no explicit consensus on the approach yet.

Contextual Notes

There is a question raised about verifying whether the given point is indeed in the plane, which may affect the direction of the discussion.

dtl42
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Homework Statement


Given some plane, [tex]3x+2y-z=6[/tex], and a point [tex](2,3,6)[/tex]

Find a line in the plane passing through that point.


Homework Equations



The Attempt at a Solution


I tried finding the vector perpendicular to the plane, [tex]<3,2,-1>[/tex], but I'm not sure what to do with it.
 
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A line passing through two points [itex]\vec{r_0}[/itex] and [itex]\vec{r_1}[/itex] is simply

[tex]\vec{r}=(1-t)\vec{r_0}+t\vec{r_1}[/tex]

You are given a point that you want the line through and you can figure out another arbitrary one right?
 
dtl42 said:
I tried finding the vector perpendicular to the plane, [tex]<3,2,-1>[/tex], but I'm not sure what to do with it.

You could use this as the direction of the line that you want.


EDIT: Read the question wrong, I thought it asked for a line passing through that point and not necessarily contained in the plane.
 
Last edited:
No, you cannot! That vector is perpendicular to the plane while the line you want is in the plane. The normal vector doesn't help at all. As jeffreydk said, a line is determined by two points. You are already given one point in the plane (did you check that it actually is in the plane?) Now choose any other point in the plane (take what ever values you like for x and y and solve for z) and use those two points to determine the line. There are, of course, an infinite number of solutions.
 

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