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Math Help - [SOLVED] I forgot how to solve quadratic equations (again)

  1. #1
    Member billym's Avatar
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    [SOLVED] I forgot how to solve quadratic equations (again)

    Find the points on the curve x^2 + 8xy + 7y^2 = 225 that are closest to the origin.

    Let D^2=f(x,y)=x^2+y^2 and g(x,y)=x^2 + 8xy + 7y^2 - 225

    So: \triangledown f=\lambda \triangledown g

    gives \lambda = \frac{x}{x+4y}=\frac{y}{7y+4x} = 4x^2+6xy+4y^2 = 0

    Can somebody do this next step for me or remind what the method is for solving these...
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  2. #2
    Member billym's Avatar
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    oops, calc error. nevermind.
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