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Math Help - Properties of tangents

  1. #1
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    Exclamation Properties of tangents

    solve for k:

    -x+k= 1/(x-1)
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  2. #2
    No one in Particular VonNemo19's Avatar
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    Quote Originally Posted by math123456 View Post
    solve for k:

    -x+k= 1/(x-1)
    Add x to both sides

    k=\frac{1}{x-1}+x

    I'm not sure if there's something elese you are supposed to do................

    If there is, just ask.
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  3. #3
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    Exclamation properties of tangents

    i mean like solve for k using the quadratic formula.
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  4. #4
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    Quote Originally Posted by math123456 View Post
    solve for k:

    -x+k= 1/(x-1)
    Add x to both sides

     <br />
k = \frac{1}{x-1}+x<br />

     <br />
k = \frac{1+x(x-1)}{x-1}<br />

     <br />
k = \frac{x^2-x+1}{x-1}<br />
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  5. #5
    No one in Particular VonNemo19's Avatar
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    I'm sorry math, but I'm not seeing how the quadratic formula has anthing to do with solving for k. Now, if we were solving for x, then the quadratic formula would be most appropriate.

    K is not quadratic at all. In fact it is linear (or even more probable; a constant).
    But for x...

    (x-1)(-x+k)=\frac{1}{x-1}*(x-1)

    -x^2+kx+x-k=1

    -x^2+kx+x-k-1=0

    x^2-kx-x+k+1=0

    x^2-(k+1)x+(k+1)=0

    The quadratic formula states that

    x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}

    Let a=1, b=-(k+1), and c=(k+1)

    You can do the rest...
    Last edited by VonNemo19; June 20th 2009 at 12:06 PM. Reason: fixed sign error
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  6. #6
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    Quote Originally Posted by VonNemo19 View Post
    I'm sorry math, but I'm not seeing how the quadratic formula has anthing to do with solving for k. Now, if we were solving for x then the quadratic formula would be most appropriate,

    K is not quadratic at all. In fact it is linear.
    But for x...

    (x-1)(-x+k)=\frac{1}{x-1}*(x-1)

    -x^2+kx+x-k=1

    -x^2+kx+x-k-1=0

    x^2-kx-x+k+1=0

    x^2-(k-1)x+(k+1)=0

    The quadratic formula states that

    x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}

    Let a=1, b=-(k-1), and c=(k+1)

    You can do the rest...
    sign mistake in last step

    x^2-(k+1)x+(k+1)=0

    Let a=1, b=-(k+1), and c=(k+1)
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  7. #7
    No one in Particular VonNemo19's Avatar
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    Quote Originally Posted by Shyam View Post
    sign mistake in last step

    x^2-(k+1)x+(k+1)=0

    Let a=1, b=-(k+1), and c=(k+1)

    Right you are. Thank you.
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  8. #8
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    Quote Originally Posted by math123456 View Post
    solve for k:

    -x+k= 1/(x-1)
    Is this the whole question, exactly as it's written in your book (or wherever it came from)? I doubt it very much since I'll bet diamonds to doughnuts that the correct answer is k = -1, 3. Next time please post the whole question so that people don't waste their time.
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