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Thread: parametrics and focal chord

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    parametrics and focal chord

    pls help rip
    P(2at,at^2) is a point on the parabola x^2=4ay. S is the focus, T is the foot of the perpendicular frpm P to the directrix, and A is the point where the tangent at P meets the y aixs.
    (i) write down the coordinates of T
    (ii) show that A is the point (0, -at^2)
    (iii) what is point S

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    Re: parametrics and focal chord

    Quote Originally Posted by sssona09 View Post
    pls help rip
    P(2at,at^2) is a point on the parabola x^2=4ay. S is the focus, T is the foot of the perpendicular frpm P to the directrix, and A is the point where the tangent at P meets the y aixs.
    (i) write down the coordinates of T
    (ii) show that A is the point (0, -at^2)
    (iii) what is point S
    I'll just give hints

    i) Use formula sheet for the normal equation as it says perpendicular at P and sub y = -a as that is the directrix equation

    ii) Use tangent equation on formula sheet and sub x = 0

    iii) (0, a) as it is the focus
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    Re: parametrics and focal chord

    Quote Originally Posted by pikachu975 View Post
    I'll just give hints

    i) Use formula sheet for the normal equation as it says perpendicular at P and sub y = -a as that is the directrix equation

    ii) Use tangent equation on formula sheet and sub x = 0

    iii) (0, a) as it is the focus
    ohh thank youuuu pikachu
    pikachu975 likes this.

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