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    A conic has eccentricity e=0.7, a focus (5,3) and directrix y=2x7. Find the points of intersection of the conic with line y=3.
    I'm really stuck on this, and have no idea even where to start.
    Any help guys?
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    (Original post by alex2100x)
    A conic has eccentricity e=0.7, a focus (5,3) and directrix y=2x7. Find the points of intersection of the conic with line y=3.
    I'm really stuck on this, and have no idea even where to start.
    Any help guys?
    eccentricity less than 1 is an ellipse...do you know the definition of e in the locus of a conic?
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    (Original post by TeeEm)
    eccentricity less than 1 is an ellipse...do you know the definition of e in the locus of a conic?
    No I do not. I also don't understand the relevance of the directrix, my lecturer didn't even mention directrix in relation to ellipses only parabolas care to enlighten me?
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    (Original post by alex2100x)
    No I do not. I also don't understand the relevance of the directrix, my lecturer didn't even mention directrix in relation to ellipses only parabolas care to enlighten me?
    an ellipse is the locus of a point whose distance from a fixed point(focus) to that from a fixed line(directrix) remains constant (e).
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    (Original post by TeeEm)
    an ellipse is the locus of a point whose distance from a fixed point(focus) to that from a fixed line(directrix) remains constant (e).
    Never seen it defined that way only seen it defined as the sum of two distances from two foci remains constant. I will check over the question again and report back!
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    (Original post by alex2100x)
    Never seen it defined that way only seen it defined as the sum of two distances from two foci remains constant. I will check over the question again and report back!
    ALL CONIC SECTIONS are defined as a locus using focus and directrix where different values of e produce different conics

    e.g.
    e=0 circle
    0<e<1 ellipse
    e=1 parabola
    e>1 hyperbola (special case e=√2 rectangular hyperbola)


    ... the sum of two distances from two foci remains constant...

    is a consequence of the definition which can easily be proven using the general definition
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    (Original post by TeeEm)
    ALL CONIC SECTIONS are defined as a locus using focus and directrix where different values of e produce different conics

    e.g.
    e=0 circle
    0<e<1 ellipse
    e=1 parabola
    e>1 hyperbola (special case e=√2 rectangular hyperbola)


    ... the sum of two distances from two foci remains constant...

    is a consequence of the definition which can easily be proven using the general definition
    didn't even know this and now I can't do any of the questions :sigh: sorry for wasting your time
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    (Original post by alex2100x)
    didn't even know this and now I can't do any of the questions :sigh: sorry for wasting your time
    my time is not wasted ...
    What course do you do and what prior knowledge do you have?
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    (Original post by TeeEm)
    my time is not wasted ...
    What course do you do and what prior knowledge do you have?
    First year undergrad. A level/gcse maths.
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    (Original post by alex2100x)
    First year undergrad. A level/gcse maths.
    undergrad in what subject?
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    (Original post by TeeEm)
    undergrad in what subject?
    Maths
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    (Original post by alex2100x)
    Maths

    o.k.


    look at this reference on conics first

    CONIC SECTION REFERENCE.pdf
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    (Original post by alex2100x)
    Maths
    next look at the link

    http://www.madasmaths.com/archive/ma...c_sections.pdf

    this is FP3 level standard, but it has full solutions.


    your question is way above further maths
 
 
 
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