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Scalar equation of plane

  1. Apr 27, 2009 #1
    Find the scalar equation of the plane which passes through the line intersection of planes x+y+z-4=0 and y+z-2= 0 that goes through (2,4,7) and satisfies the conditions
    a) it is 2 units from the orgin
    b) it is 3 units from the point a(5,-3,7)

    I would really apprecaite if some toke me through the steps on how the solve the problem

    Thank You
  2. jcsd
  3. Apr 28, 2009 #2


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    Hi SSUP21! :wink:

    Show us what you've tried, and where you're stuck, and then we'll know how to help! :smile:
  4. Apr 28, 2009 #3
    and thanks for replying for this one i knew that to find a plane i needed a normal and a point
    the intersection of the given planes is a vector in direction of our plane so i cross product their normals

    i need another vector i had a point i needed another point so I assume that any point on the intersection of the two give planes is also on the third plane so let y = 0 and solved to find the point
    then i found my second vector by doing cross product of the two point
    then substituted in our given point to solve for D in equation ax + by+ cz + D=0

    i have my plane but im stuck at trying to satisfy the two conditions
  5. Apr 29, 2009 #4


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    Hi SSUP21! :smile:
    Yes, that's absolutely right. :smile:
    mmm … I don't really follow what you're doing. :redface:

    In fact, looking at the question more carefully, I don't really understand that either …
    there's only one plane through that line that goes through (2,4,7), so what do a) and b) have to do with it?? :confused:
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