Finding a Point on Line P Normal to Plane 2x-y+2z=-2

In summary, the student attempted to find the point in the plane at which a normal to the plane passes through (3, 2, 1). They got t=-8 when solving for t. They also made a mistake in their parametric equation for z. Finally, they had problems with their equations for x, y, and z.
  • #1
MozAngeles
101
0

Homework Statement



Find a point in which the line through P(3,2,1) normal to the plane 2x-y+2z=-2

Homework Equations





The Attempt at a Solution


n=<2,-1,2>, so x=3+2t y=2-t z=1-2t
so then i have point (3+2t,2-t,1-2t)
i plug that into the plane, solve for t, which i get to be -8,

so then (x,y,z) for t=-8 (-13,10,17) but this answer is differnet from the back of the book. I don't have any clue as to what i am doing wrong. any help would be nice thanksss :D
 
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  • #2
MozAngeles said:

Homework Statement



Find a point in which the line through P(3,2,1) normal to the plane 2x-y+2z=-2
I think some words are missing in your problem description. From the work below, it appears that you want to find the point in the plane at which a normal to the plane passes through (3, 2, 1).
MozAngeles said:

Homework Equations





The Attempt at a Solution


n=<2,-1,2>, so x=3+2t y=2-t z=1-2t
so then i have point (3+2t,2-t,1-2t)
i plug that into the plane, solve for t, which i get to be -8,

so then (x,y,z) for t=-8 (-13,10,17) but this answer is differnet from the back of the book. I don't have any clue as to what i am doing wrong. any help would be nice thanksss :D
I get t = -8/9.
 
  • #3
yes i have to find where the line meets the plane, so am i right with my equations for x,y, and z. but when i plug them into the equation for the plane i keep on getting t=-8.
 
  • #4
Your parametric equations for the line are fine, but you have made a mistake in solving for t at the point where the line intersects the plane. Show us your work on solving for t.
 
  • #5
2(3+2t)-(2-t)+2(1-2t)=-2
6+4t-2+t+2-4t=-2
t=-8
 
  • #6
I didn't notice before, but you have a mistake in your parametric equation for z. It should be z = 1 + 2t. You have z = 1 - 2t.
 
  • #7
Ohhhh k. Thanks.
 

1. How do you find a point on a line that is normal to a given plane?

To find a point on a line that is normal to a plane, you can start by finding the normal vector of the plane. This can be done by rearranging the plane's equation into the form of Ax + By + Cz = D, where A, B, and C are the coefficients of x, y, and z, respectively. Then, the normal vector will be (A, B, C).

Next, choose any point on the line and find its position vector. Then, using the dot product, you can find the distance between the given plane and the point on the line. The point with this distance that is also perpendicular to the plane will be the desired point on the line.

2. Can you explain the concept of a normal vector in this context?

In this context, a normal vector is a vector that is perpendicular to the plane. It is used to find a point on a line that is normal to the plane. This vector is important because it helps determine the distance between the plane and the point on the line, which is essential in finding the desired point.

3. What is the significance of finding a point on a line that is normal to a plane?

Finding a point on a line that is normal to a plane is important in many applications, such as computer graphics, engineering, and architecture. It allows for the creation of 3D models and designs that are accurate and precise. It also helps in solving various geometric problems and equations.

4. Are there any specific steps or formulas to follow for finding a point on a line normal to a plane?

Yes, there are specific steps and formulas to follow. First, find the normal vector of the plane. Then, choose any point on the line and find its position vector. Next, use the dot product to find the distance between the plane and the point on the line. Finally, find the point with this distance that is also perpendicular to the plane, which will be the desired point on the line.

5. Can this method be used to find a point on a line that is normal to any plane?

Yes, this method can be used to find a point on a line that is normal to any plane. As long as the equation of the plane is given, the steps and formulas mentioned above can be applied to find the desired point. However, the normal vector may vary for different planes, so it is important to find the normal vector first before proceeding with the method.

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