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Math Help - curves

  1. #1
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    curves

    show that the curves 3x^2+2x-3y^2=1 and 6xy+2y=0 are orthogonal (i.e. there slopes everywhere are perpendicular)
    thank you, your help is very appreciated!
    Last edited by mxhockey140; December 15th 2008 at 03:43 PM.
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  2. #2
    Member billa's Avatar
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    If you take the derivatives of both curves wrt x then the derivative of the first curve is (3x+1)/(3y) and the derivative of the second curve wrt x is
    (-3y)/(3x+1). So the slopes are opposite reciprocals. This means they are perpendicular. Hope this helps, someone else will hopefully explain it better.
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  3. #3
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    im sorry i had a typo. the first equation i forgot to put = 1, i dont know if that changes anything at all or not..
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  4. #4
    Member billa's Avatar
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    nope because the derivative of a constant is still zero
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  5. #5
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    thank you!
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