Equation of a plane involving a known line and a known point

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SUMMARY

The equation of the plane containing the line defined by r(t) = (2-t, 1+t, t) and the point (1,0,1) can be derived using vector analysis. The direction vector a parallel to the line is identified as (-1, 1, 1), while the vector b from the origin to the point is (1, 0, 1). The normal vector n is calculated using the cross product of vectors a and b, resulting in n = (1, 2, -1). The scalar equation of the plane is established as x + 2y - z = 0, confirming the plane's orientation in three-dimensional space.

PREREQUISITES
  • Understanding of vector operations, specifically cross products.
  • Familiarity with parametric equations of lines in three-dimensional space.
  • Knowledge of scalar equations of planes.
  • Basic skills in linear algebra and geometry.
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  • Study vector cross product calculations in detail.
  • Learn how to derive equations of planes from given points and vectors.
  • Explore parametric equations and their applications in three-dimensional geometry.
  • Investigate the geometric interpretation of normal vectors in relation to planes.
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Students and educators in mathematics, particularly those focused on geometry and linear algebra, as well as anyone solving problems related to three-dimensional space and vector analysis.

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Homework Statement


Find the equation of the plane which contains the line r(t) = (2-t, 1+t, t) and the point (1,0,1).

The Attempt at a Solution


Since r(t) = (2-t, 1+t, t), we know that vector a, which is parallel to the line, is (-1, 1, 1).
I'm assuming that since the point is (1,0,1), that means if we look to that point from the origin (0,0,0) we will have vector b = (1,0,1).
Okay so with two vectors a and b, I can find a vector n such that n is orthogonal to vectors a and b. So a x b = (1-0,1+1,0-1) = (1,2-1) = vector n.
The scalar equation of a plane is a(x-x0) + b(y-y0 + c(z-z0). So x + 2y -z = 0...

But somehow I have a feeling that my result is wrong. Is there supposed to be a "y" at all in the equation for this plane? Please advise. Thanks in advance!
 
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The point B(1, 0, 1) is in the plane, but the vector OB isn't. From your equation for the line you can easily find two points in the plane, say (2, 1, 0) and (1, 2, 1), just by supplying values of t.

Form vectors between one of the points and each of the other two. Now cross these vectors to get a vector normal to both of these. Use this normal vector and anyone of the points to get the equation of the plane.

You didn't show your work in getting the cross product a X b, so the normal you show is somewhat suspect.
 

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