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Math Help - equation of inverse

  1. #1
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    equation of inverse

    equation of inverse of  y= 1/(x+2) -1

    i know you swap the x and y and then solve for y but I get stuck.
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  2. #2
    Like a stone-audioslave ADARSH's Avatar
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    -Swap x and y
    so
     <br />
x=1/(y+2)-1<br />
    Next add one to both sides

    so

    x+1=\frac{1}{y+2}

    Now Multiply both sides with

    \frac{y+2}{x+1}

     <br />
y+2 = \frac{1}{x+1}<br />

    Deduct 2 from both sides


    y= \frac{1}{x+1} - 2

    the thing on RHS is your inverse
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  3. #3
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    thank you! I got to the point of multiplying and I just multiplied by the recipocal so I got something like xy = -y +2x -1 If that makes any sense (obv.wrong.)
    I understand know so thank you.
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  4. #4
    Like a stone-audioslave ADARSH's Avatar
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    Quote Originally Posted by brentwoodbc View Post
    I understand know so thank you.
    I think it will be clear

    (x+1)=\frac{1}{y+2}

    (x+1)\frac{(y+2)}{(x+1)}=\frac{(y+2)}{(y+2)(x+1)}

    (y+2)=\frac{1}{(x+1)}

    (y)=\frac{1}{(x+1)}-2

    (y)=\frac{-2x-1}{(x+1)}

    f^{-1}(x)=\frac{-2x-1}{(x+1)}
    Last edited by ADARSH; February 11th 2009 at 11:21 PM. Reason: doubt
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