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    • Thread Starter

    8) The point P lies on the rectangular hyperbola xy = c^2, where c > 0. The tangent to the rectangular hyperbola at the point P(ct, c/t), t > 0, cuts the x axis at the point X and cuts the y-axis at the point Y.

    (a) Find in terms of c and t, the coordinates of X and Y

    y = c^2 /x
    dy/dx = - c^2/x^2
    dy/dx = - c^2 / c^2 t^2
    dy/dx = - 1 / t^2

    y - c/t = -1/t^2 (x-ct)
    yt - c = - x/t + c
    yt^2 - ct = -x + c

    apparently this is wrong... go on...
    • PS Helper

    PS Helper
    You should have -x+ct on the RHS of the last line.
    • Study Helper

    Study Helper
    Now that nuodai has pointed it out, we can all see it, so this is going to be very expensive; seeing as you didn't restrict your offer to the first one!

    Did he pay lol??
    • PS Helper

    PS Helper
    (Original post by cheeseandbiscuits)
    Did he pay lol??
    Nope (nor did I expect him to), but a mod removed all the money stuff... for obvious reasons.
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Updated: October 1, 2010
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