Finding an equation of the plane (Linear Algebra)

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SUMMARY

The discussion focuses on finding the equation of a plane with a y-intercept of -5, parallel to a plane defined by points P(3, -1, 2), Q(0, 2, 1), and R(5, 2, 0). The directional vectors derived from the points are u = PQ = (-3, 3, -1) and v = PR = (2, 3, -2). The normal vector calculated is n = u x v = (3, 8, 15). The equation of the plane is established as 3x + 8y + 15z - 31 = 0, but the y-intercept condition requires further adjustment to ensure the plane passes through the point (0, -5, 0).

PREREQUISITES
  • Understanding of vector operations, specifically cross products
  • Familiarity with the equation of a plane in the form ax + by + cz + d = 0
  • Knowledge of how to determine the normal vector from directional vectors
  • Ability to manipulate plane equations to satisfy specific conditions, such as intercepts
NEXT STEPS
  • Review vector cross product calculations in linear algebra
  • Study how to derive the equation of a plane from a normal vector and a point
  • Learn about adjusting plane equations to meet specific intercept conditions
  • Explore examples of parallel planes and their properties in three-dimensional space
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Students studying linear algebra, particularly those working on plane equations and vector operations, as well as educators seeking to clarify concepts related to planes in three-dimensional geometry.

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Homework Statement


Find an equation of the plane that has y-intercept -5 and is parallel to the plane containing the points P(3, -1, 2), Q(0, 2, 1) and R(5, 2, 0)

Homework Equations



ax + by + cz + d = 0

The Attempt at a Solution



I got two directional vectors
u = PQ = (-3, 3, -1)
v = PR = (2, 3, -2)

n = u x v = (-3, -8, -15) which is also equal to (3, 8, 15) because it's a nonzero multiple of n

So putting P and the norm together, I get
3(x-3) + 8(y+1) + 15(z-2) = 0
3x + 8y + 15z - 31 = 0

Now I'm stuck. I have no idea what to do with y-intercept of -5. A push in the right direction would be nice.
 
Physics news on Phys.org
The point P is not in your plane. It is in a parallel plane. The y-intercept (0, -5, 0) is the only point that is presented as being in your plane.
 

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