Results 1 to 2 of 2

Math Help - if the planes are perpendicular, what is k?

  1. #1
    Junior Member
    Joined
    Nov 2010
    Posts
    58

    if the planes are perpendicular, what is k?

    Determine value of k when thehse are perpendicular:
    [x,y,z] = [1+4s+kt, 2+2s+t, 7+2t]
    and
    [x,y,z] = [4,1,-1] + s[1,0,5] + t[0,-3,3]

    I learned that in 2 and 3D, two lines are perpendicular only if, after solving for the t in front of the direction vector, x=x , y=y and z=z
    My attempt was to Cross product the direction vecotrs in each of the equations, and then dot product those values to find k, since if they are perpend. then dot product=0
    I'm not sure how they ended up with k = 31/3
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    earboth's Avatar
    Joined
    Jan 2006
    From
    Germany
    Posts
    5,830
    Thanks
    123
    Quote Originally Posted by TN17 View Post
    Determine value of k when thehse are perpendicular:
    [x,y,z] = [1+4s+kt, 2+2s+t, 7+2t]
    and
    [x,y,z] = [4,1,-1] + s[1,0,5] + t[0,-3,3]

    I learned that in 2 and 3D, two lines are perpendicular only if, after solving for the t in front of the direction vector, x=x , y=y and z=z
    My attempt was to Cross product the direction vecotrs in each of the equations, and then dot product those values to find k, since if they are perpend. then dot product=0
    I'm not sure how they ended up with k = 31/3
    I'm pretty sure that this is a typo. I've got k = -12.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Angle between planes and line of intersection of planes.
    Posted in the Advanced Algebra Forum
    Replies: 1
    Last Post: September 6th 2011, 01:08 PM
  2. Parallel planes and intersecting planes
    Posted in the Calculus Forum
    Replies: 2
    Last Post: June 8th 2010, 09:25 AM
  3. Replies: 1
    Last Post: May 4th 2010, 01:43 PM
  4. Determine whether the planes are perpendicular
    Posted in the Advanced Algebra Forum
    Replies: 3
    Last Post: March 14th 2010, 06:43 PM
  5. How to find out of planes are perpendicular
    Posted in the Pre-Calculus Forum
    Replies: 1
    Last Post: April 22nd 2009, 01:34 PM

Search Tags


/mathhelpforum @mathhelpforum