Lines and Planes: How Do They Intersect?

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SUMMARY

The discussion focuses on the intersection of two parametric lines, L_1 and L_2, with a defined plane P. The first line is represented as L_1: (x, y, z) = (-4, 3, 4)t + (7, 2, -1), and the second line as L_2: (x, y, z) = (-3, 5, 5)s + (-1, 62, -11). The plane equation is given by P: (x, y, z) dotted with (9, -2, 3) = -4. The solution for the intersection point of L_1 and P was found to be t = 2, and further steps are needed to verify if this point lies on the plane and to calculate the shortest distance between L_1 and L_2.

PREREQUISITES
  • Understanding of parametric equations for lines
  • Knowledge of vector dot products
  • Familiarity with solving equations for unknowns
  • Basic concepts of distance between lines in 3D space
NEXT STEPS
  • Verify if the intersection point of L_1 and P lies on the plane using the plane equation
  • Calculate the shortest distance between two skew lines using vector projections
  • Explore the method of generating points on parametric lines
  • Study the implications of line and plane intersections in three-dimensional geometry
USEFUL FOR

Students studying geometry, particularly in three-dimensional space, mathematicians interested in vector analysis, and educators teaching concepts of lines and planes in advanced mathematics.

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Homework Statement



The Question Says:

Given tow lines and a plane:

The First Line is:L_1:(x y z):= (-4 3 4)*t +(7 2 -1)

The Second Line:L_2:(x y z):=( -3 5 5)*s +(-1 62 -11)

The Plane is :P:(x y z)dotted with(9 -2 3)=-4

(A)At which point do L_1 and P intersect? Check if this point lies in the plane P

(B) What is the shortest distance between L_1 and L_2?
The attempt at a solution:

For Part A

I have tried to do the following:

(-4*t+7)*(9)
(3*t+2)*(-2)
(4*t-1)*(3)
all equal to =-4

then solve for t
t=2

I am not sure if this is correct, for the next part "Check if this point lies in the plane P" I am not sure how to do so

for Part B I didn't try it yet , but I will do after a bit.
 
Last edited:
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These line equations are parametric, so they say that if you choose any t (or s in L_2), you'll get a point on the line. The plane equations are implicit, so they say that for any point, if the equation is correct for it, that point is on the plane.
Now you have a method to generate a point on the line and a method to check if a point is on a plane. If you combine the two, you get an equation with a single unknown t. Since you're asked for a point, don't forget to generate it with the line function.
 

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