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Plane and 3d vector

  1. Aug 1, 2014 #1
    1. The problem statement, all variables and given/known data
    problem 1:
    given the straight line r whose equation is r=<3+2t, 4+2t, -1-t>

    0.Determine A, intersection of the plane yz
    0.1the parameter value at A is t=
    0.2therefore A=(...,...,...)

    1.we want to re-parametrize r (be u the new parameter) so that:
    1.1the new direction vector e be a unit vector, then e = <...,...,...>
    1.2 as u increases the x coordinates increases. it follows that e=<...,...,...>
    1.3 A be the new origin point. the new equation is: r=<.....,.....,.....>

    2. Determine B and C, intersections of r with the zx and xy plane respectively.
    2.1 parameter values at the two points are Ub=....... Uc=.......
    2.2 distances AB and AC are therefore dAB=.......... dAC=........
    2.3 Points coordinates are B= (.....,.....,.....) C=(......,......,.....)

    3. The attempt at a solution
    A at x=0 hence 3+2t=0 therefore A at t=-3/2
    point A(0,1,1/3)
    direction vector d=(2,2,-1)

    for 1.1 the formula to be applied is v/|v| but i don't know whether it should be applied to the direction vector or to the original equation. also question 1.2 is problematic for me since i don't understand what is asked for. any help is much appreciated
     
  2. jcsd
  3. Aug 1, 2014 #2

    verty

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    Homework Helper

    For 1.1, if t increases, in what direction does the point r(t) travel? They want a unit vector in this direction.
    For 1.2, you may need to flip that vector around so that it points toward the positive x axis.
     
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