Results 1 to 3 of 3

Math Help - Finding the coordinates of a point

  1. #1
    Newbie
    Joined
    Jan 2006
    Posts
    2

    Finding the coordinates of a point

    I am given a point P(x1,y1). I have to find the coordinates of a point at
    a distance say DIS from it. The only thing we are given is that this
    point maintains the angles XO,YO with the x ,y axis respectively. I told
    my boss that I am having trouble with this but he said that it is
    supposed to be simple and that I have all the information I need. I always
    used to consider myself a good math student until today (completed my
    education and always got good grades in Math). But now I am starting to
    doubt my math capability! Please help me figure out how to do this. Its actually in 3 dimensions but I figured it would be
    easy to do this in 2D first. How do we find the coordinates of the
    point A?

    /A(x,y?)
    /
    DIS /
    /
    /
    /XO
    /________________________x axis
    P( x1,y1)
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Grand Panjandrum
    Joined
    Nov 2005
    From
    someplace
    Posts
    14,972
    Thanks
    4
    Quote Originally Posted by Mathasker
    I am given a point P(x1,y1). I have to find the coordinates of a point at
    a distance say DIS from it. The only thing we are given is that this
    point maintains the angles XO,YO with the x ,y axis respectively. I told
    my boss that I am having trouble with this but he said that it is
    supposed to be simple and that I have all the information I need. I always
    used to consider myself a good math student until today (completed my
    education and always got good grades in Math). But now I am starting to
    doubt my math capability! Please help me figure out how to do this. Its actually in 3 dimensions but I figured it would be
    easy to do this in 2D first. How do we find the coordinates of the
    point A?

    /A(x,y?)
    /
    DIS /
    /
    /
    /XO
    /________________________x axis
    P( x1,y1)

    The points DIS from A(u,v) define a circle with equation:

    (x-u)^2+(x-v)^2=DIS^2

    The condition that the line PA make an angle XO with the
    x-axis is that the line PA has slope \tan (XO). So
    now find the equation of a line of slope \tan(XO) which passes
    through A(u,v), and then solve for the points of intersection of
    this line with the circle.

    RonL
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor
    Joined
    Apr 2005
    Posts
    1,631
    Quote Originally Posted by Mathasker
    I am given a point P(x1,y1). I have to find the coordinates of a point at
    a distance say DIS from it. The only thing we are given is that this
    point maintains the angles XO,YO with the x ,y axis respectively. I told
    my boss that I am having trouble with this but he said that it is
    supposed to be simple and that I have all the information I need. I always
    used to consider myself a good math student until today (completed my
    education and always got good grades in Math). But now I am starting to
    doubt my math capability! Please help me figure out how to do this. Its actually in 3 dimensions but I figured it would be
    easy to do this in 2D first. How do we find the coordinates of the
    point A?

    /A(x,y?)
    /
    DIS /
    /
    /
    /XO
    /________________________x axis
    P( x1,y1)
    See if I understand your question:
    ---line segment DIS is DIS long. [ :-) ].
    ---top endpoint of DIS is A(x,y)
    ---bottom endpoint of DIS is P(x1,y1)
    ---angle included by DIS and a horizontal line is XO
    ---point P is not on the x-axis. Otherwise, if it is, then y1 = 0.
    ---you like to solve for the x and y of point A

    If I got the question, then:
    x = x1 +(DIS)*cos(X0)
    y = y1 +(DIS)*sin(X0)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 6
    Last Post: September 12th 2009, 07:23 AM
  2. Determine the coordinates of the point
    Posted in the Algebra Forum
    Replies: 1
    Last Post: May 4th 2009, 07:28 AM
  3. turning point, coordinates
    Posted in the Calculus Forum
    Replies: 2
    Last Post: May 2nd 2009, 11:20 AM
  4. Find Coordinates of Point B
    Posted in the Geometry Forum
    Replies: 3
    Last Post: October 4th 2008, 04:24 AM
  5. Find Coordinates of Point B
    Posted in the Geometry Forum
    Replies: 2
    Last Post: September 26th 2008, 05:00 AM

Search Tags


/mathhelpforum @mathhelpforum