Results 1 to 5 of 5

Math Help - equation of the line

  1. #1
    Member
    Joined
    Dec 2009
    Posts
    122

    equation of the line

    Can you help me find the equation of the line perpendicular to the line x=4, and passing through the point (4, 2)?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Member
    Joined
    Apr 2009
    Posts
    136
    Awards
    1
    The equation x = 4 has a gradient that is undefined.

    The perpendicular to this line would be 0, so

    using the point slope form of an equation at the point (4,2)

    y - y1 = m (x- x1)

    y - 2 = 0 (x - 4)

    y - 2 = 0

    y = 2 is the equation of the line perpendicular to x = 4 at the point (4, 2)
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member Bacterius's Avatar
    Joined
    Nov 2009
    From
    Wellington
    Posts
    927
    Joel, be more careful in the choice of your words :
    The perpendicular to this line would be 0, so
    is meaningless, and more confusing than ever for someone trying to understand line equations.

    The slope of the perpendicular to this line equals 0, so
    Follow Math Help Forum on Facebook and Google+

  4. #4
    MHF Contributor

    Joined
    Apr 2005
    Posts
    16,242
    Thanks
    1795
    Quote Originally Posted by jay1 View Post
    Can you help me find the equation of the line perpendicular to the line x=4, and passing through the point (4, 2)?
    The line x= 4 is vertical, parallel to the y axis so x is not changing.

    The line perpendicular to it is horizontal, parallel to the x axis so y is not changing. Since y= 2 at the point (4, 2) and y is not changing, the equation is y= 2.
    Follow Math Help Forum on Facebook and Google+

  5. #5
    MHF Contributor

    Joined
    Apr 2005
    Posts
    16,242
    Thanks
    1795
    Quote Originally Posted by Joel View Post
    The equation x = 4 has a gradient that is undefined.

    The perpendicular to this line would be 0, so
    The gradient of the line perpendicular to this line would be 0.

    using the point slope form of an equation at the point (4,2)

    y - y1 = m (x- x1)

    y - 2 = 0 (x - 4)

    y - 2 = 0

    y = 2 is the equation of the line perpendicular to x = 4 at the point (4, 2)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 4
    Last Post: May 12th 2011, 01:18 PM
  2. Replies: 1
    Last Post: March 18th 2011, 11:36 AM
  3. Replies: 11
    Last Post: June 2nd 2009, 07:08 PM
  4. Replies: 5
    Last Post: October 13th 2008, 11:16 AM
  5. equation of a line perpendicular to the line defined
    Posted in the Pre-Calculus Forum
    Replies: 2
    Last Post: June 6th 2007, 10:02 AM

Search Tags


/mathhelpforum @mathhelpforum