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

  • Thread starter dtl42
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In summary, to find a line in a plane passing through a given point, you need to choose another point in the plane and use the equation \vec{r}=(1-t)\vec{r_0}+t\vec{r_1} to determine the line. The normal vector of the plane will not help in this situation.
  • #1
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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  • #2
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?
 
  • #3
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:
  • #4
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.
 

1. What is meant by "Find Line in Plane Passing Through (2,3,6)"?

When we say "Find Line in Plane Passing Through (2,3,6)", we are referring to finding the equation of a straight line that lies on a specific plane and passes through the point (2,3,6). This means that all the points on the line will also lie on the given plane and must pass through the point (2,3,6).

2. How do you find the equation of a line passing through a specific point?

To find the equation of a line passing through a specific point, we need to know the coordinates of that point and the slope of the line. With this information, we can use the point-slope form of a line equation, y - y1 = m(x - x1), where (x1, y1) are the coordinates of the given point and m is the slope. We can also use other forms of the line equation, such as slope-intercept form or two-point form, depending on the given information.

3. How do you determine a plane passing through a given point?

To determine a plane passing through a given point, we need to know the coordinates of that point and the normal vector to the plane. The normal vector is a vector that is perpendicular to the plane. With this information, we can use the point-normal form of a plane equation, a(x - x1) + b(y - y1) + c(z - z1) = 0, where (x1, y1, z1) are the coordinates of the given point and a, b, and c are the components of the normal vector.

4. Can there be multiple lines passing through a given point and lying on the same plane?

Yes, there can be infinite lines passing through a given point and lying on the same plane. This is because a plane is a two-dimensional surface and a line is a one-dimensional object. As long as the line lies on the plane and passes through the given point, it can be considered a solution.

5. How do you know if a line and a plane are parallel or perpendicular?

If the line lies entirely on the plane, then it is parallel to the plane. If the line is perpendicular to the normal vector of the plane, then it is perpendicular to the plane. In other words, the dot product between the line's direction vector and the normal vector of the plane is 0 for perpendicular lines, and it is non-zero for parallel lines.

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