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    ACB is a straight line.
    A is the point (0, 8), and B is the point (4, 0)
    C is the midpoint of AB.
    Line DCE is perpendicular to line ACB.

    Work out the equation of line DCE.
    ------------------------------------------------------------------------
    What I did was:
    I worked out that mAB = -2, therefore mDCE = 1/2
    The midpoint of AB(which is C) is (2,4)
    I then substituted (2,4) into y = 1/2x +c
    This gave me y = 1/2x +3 as the equation of the line DCE.

    I checked the mark scheme and their answer is y = 1/2x -2.
    I was doing another of their questions and the mark scheme was definitely wrong then.

    Was my method/answer correct, if not, where did I go wrong?
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    (Original post by bintabii)
    ACB is a straight line.
    A is the point (0, 8), and B is the point (4, 0)
    C is the midpoint of AB.
    Line DCE is perpendicular to line ACB.

    Work out the equation of line DCE.
    ------------------------------------------------------------------------
    What I did was:
    I worked out that mAB = -2, therefore mDCE = 1/2
    The midpoint of AB(which is C) is (2,4)
    I then substituted (2,4) into y = 1/2x +c
    This gave me y = 1/2x +3 as the equation of the line DCE.

    I checked the mark scheme and their answer is y = 1/2x -2.
    I was doing another of their questions and the mark scheme was definitely wrong then.

    Was my method/answer correct, if not, where did I go wrong?
    Your answer is definitely correct. (2,4) isn't even a point on their line.
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    (Original post by SeanFM)
    Your answer is definitely correct. (2,4) isn't even a point on their line.
    Thanks for checking!
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    (Original post by bintabii)
    ACB is a straight line.
    A is the point (0, 8), and B is the point (4, 0)
    C is the midpoint of AB.
    Line DCE is perpendicular to line ACB.

    Work out the equation of line DCE.
    ------------------------------------------------------------------------
    What I did was:
    I worked out that mAB = -2, therefore mDCE = 1/2
    The midpoint of AB(which is C) is (2,4)
    I then substituted (2,4) into y = 1/2x +c
    This gave me y = 1/2x +3 as the equation of the line DCE.

    I checked the mark scheme and their answer is y = 1/2x -2.
    I was doing another of their questions and the mark scheme was definitely wrong then.

    Was my method/answer correct, if not, where did I go wrong?
    I can also confirm that you are right. Logic is flawless - either way plot it, work it out algebraically, same answer.
    • Thread Starter
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    (Original post by CraigFowler)
    I can also confirm that you are right. Logic is flawless - either way plot it, work it out algebraically, same answer.
    Thanks!
 
 
 
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