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    the distance PS/ the distance PM (PS/PM) = e

    what is e? I dont understand: is it the the distance between S & M?
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    (Original post by Maths&physics)
    the distance PS/ the distance PM (PS/PM) = e

    what is e? I dont understand: is it the the distance between S & M?
    e is a constant called the eccentricity. It is the ratio of \frac{PS}{PM} as shown in your diagram.
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    (Original post by ManLike007)
    e is a constant called the eccentricity. It is the ratio of \frac{PS}{PM} as shown in your diagram.
    PS is the distance between points P & S?
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    (Original post by Maths&physics)
    PS is the distance between points P & S?
    Yes

    PS is the distance between P and S

    PM is the distance between P and M
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    (Original post by ManLike007)
    Yes

    PS is the distance between P and S

    PM is the distance between P and M
    what is a distance divided by a distance?
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    (Original post by Maths&physics)
    what is a distance divided by a distance?
    Distance divided by distance would give you no units so it's a ratio
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    (Original post by ManLike007)
    Distance divided by distance would give you no units so it's a ratio
    because the units would cancel?

    superb.

    the ratio will always be the same for the same ellipse but different if the ellipse is a different size?
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    (Original post by Maths&physics)
    because the units would cancel?
    Yh so the base unit for distance is meters so \frac{m}{m}=1, hence it's dimensionless.

    (Original post by Maths&physics)
    superb.
    Indeed

    (Original post by Maths&physics)
    the ratio will always be the same for the same ellipse but different if the ellipse is a different size?
    I assume so yes (though you may want to check) so using your diagram, it's worth noting that

    If 0<e<1, the point P describes an ellipse.

    If e=1, the point P describes a parabola.

    If e>1 the point P describes a hyperbola.

    I don't know this off the top of my head so credit to the FP3 text book.
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    (Original post by ManLike007)
    Yh so the base unit for distance is meters so \frac{m}{m}=1, hence it's dimensionless.



    Indeed



    I assume so yes (though you may want to check) so using your diagram, it's worth noting that

    If 0<e<1, the point P describes an ellipse.

    If e=1, the point P describes a parabola.

    If e>1 the point P describes a hyperbola.

    I don't know this off the top of my head so credit to the FP3 text book.
    thanks
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    (Original post by ManLike007)
    Yh so the base unit for distance is meters so \frac{m}{m}=1, hence it's dimensionless.

    Indeed



    I assume so yes (though you may want to check) so using your diagram, it's worth noting that

    If 0<e<1, the point P describes an ellipse.

    If e=1, the point P describes a parabola.

    If e>1 the point P describes a hyperbola.

    I don't know this off the top of my head so credit to the FP3 text book.
    How would e (the ratio) look like in relation to the graph? Thanks
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    (Original post by ManLike007)
    Yh so the base unit for distance is meters so \frac{m}{m}=1, hence it's dimensionless.



    Indeed



    I assume so yes (though you may want to check) so using your diagram, it's worth noting that

    If 0<e<1, the point P describes an ellipse.

    If e=1, the point P describes a parabola.

    If e>1 the point P describes a hyperbola.

    I don't know this off the top of my head so credit to the FP3 text book.
    and is the x coordinate of the directrix a/e?
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    I was overthinking it. ive just watched a tutorial which explains it clearly. thanks
 
 
 
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