Where Did I Go Wrong? Solving Equations with Multiple Variables

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Homework Help Overview

The discussion revolves around finding the scalar equation of a plane that passes through a specific point and is perpendicular to a given line of intersection of two planes. The subject area includes vector equations and the properties of planes in three-dimensional space.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the requirements for determining the equation of a plane, including the need for a point on the plane and a normal vector. There are questions about the correctness of previous work and the form of the equation being sought.

Discussion Status

Some participants express confidence in their calculations, while others seek clarification on the form of the equation. There is an ongoing exploration of the correct representation of the plane's equation, with suggestions to convert it into a scalar form.

Contextual Notes

Participants are working under the constraints of a homework problem that requires specific forms for the plane's equation. There is an emphasis on ensuring that the derived equation meets the problem's requirements.

ttpp1124
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Homework Statement
a. Determine an equation of the line of intersection of the planes 4x − 3y − z = 1 and 2x + 4y + z =5.
b. Find the scalar equation for the plane through (5, −2, 3) and perpendicular to that line of intersection.

I solved a, I'm not sure how to attempt b :/
Relevant Equations
n/a
IMG_3647.jpg
 
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ttpp1124 said:
b. Find the scalar equation for the plane through (5, −2, 3) and perpendicular to that line of intersection.
You have an equation of the line of intersection of the two planes. The plane you're looking for in part b is perpendicular to the line of intersection, thus a normal to that plane is parallel to the line you found.
It shouldn't be difficult to find an equation of a plane if you know 1) a point on the plane, and 2) a normal to that plane.
For part a, did you check your work? Any point on the line should be on both planes, and the direction vector of the line should be perpendicular to the normal of the two planes.
 
Mark44 said:
You have an equation of the line of intersection of the two planes. The plane you're looking for in part b is perpendicular to the line of intersection, thus a normal to that plane is parallel to the line you found.
It shouldn't be difficult to find an equation of a plane if you know 1) a point on the plane, and 2) a normal to that plane.
For part a, did you check your work? Any point on the line should be on both planes, and the direction vector of the line should be perpendicular to the normal of the two planes.
I did check my work for part a, I'm confident in my answer.
Since 𝐍=(1,−6,22)N=(1,−6,22) is a normal to the plane its equation is
𝐍⋅(𝑥,𝑦,𝑧)−(5,−2,3))=0.
 
ttpp1124 said:
I did check my work for part a, I'm confident in my answer.
Since 𝐍=(1,−6,22)N=(1,−6,22) is a normal to the plane its equation is
𝐍⋅(𝑥,𝑦,𝑧)−(5,−2,3))=0.
But don't leave it in that form, since that problem asks for the scalar equation of the plane. This will be either Ax + By + Cz = D or ##A(x - x_0) + B(y - y_0) + C(z - z_0) = 0##, where ##(x_0, y_0, z_0)## is the known point and <A, B, C> is a normal to the plane.
 
ttpp1124 said:
1(x-5)-6(y+2)+22(z-3)
That's not an equation.
 
Mark44 said:
That's not an equation.
can you tell me where I went wrong?

EDIT: 𝑥−6𝑦+22𝑧=83 is my answer.
 
ttpp1124 said:
can you tell me where I went wrong?

EDIT: 𝑥−6𝑦+22𝑧=83 is my answer.
That's better.
 

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