Results 1 to 9 of 9

Math Help - Rational expressions

  1. #1
    Junior Member Rheanna's Avatar
    Joined
    Nov 2008
    Posts
    36
    Awards
    1

    Rational expressions

    I've been looking at the examples in the book and can't find any examples on similar to this problem and I'm trying to figure out how I would go about solving it. Thank You

    r- r^2-1/r / 1- r-1/r everything is all divided but I don't know how to write the tags in format.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    A riddle wrapped in an enigma
    masters's Avatar
    Joined
    Jan 2008
    From
    Big Stone Gap, Virginia
    Posts
    2,551
    Thanks
    12
    Awards
    1
    Quote Originally Posted by Rheanna View Post
    I've been looking at the examples in the book and can't find any examples on similar to this problem and I'm trying to figure out how I would go about solving it. Thank You

    r- r^2-1/r / 1- r-1/r everything is all divided but I don't know how to write the tags in format.
    Hi Rheanna,

    Parentheses might help. Is this your rational expression?

    \dfrac{r-r^2-\dfrac{1}{r}}{1-r-\dfrac{1}{r}}
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member Rheanna's Avatar
    Joined
    Nov 2008
    Posts
    36
    Awards
    1
    Quote Originally Posted by masters View Post
    Hi Rheanna,

    Parentheses might help. Is this your rational expression?

    \dfrac{r-r^2-\dfrac{1}{r}}{1-r-\dfrac{1}{r}}
    top one is r square 2-1/r
    bottom one is r-1/r

    it comes out to 1 as the answer but i'm trying to figure out how to come up with that.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    A riddle wrapped in an enigma
    masters's Avatar
    Joined
    Jan 2008
    From
    Big Stone Gap, Virginia
    Posts
    2,551
    Thanks
    12
    Awards
    1
    Quote Originally Posted by masters View Post
    Hi Rheanna,

    Parentheses might help. Is this your rational expression?

    \dfrac{r-r^2-\dfrac{1}{r}}{1-r-\dfrac{1}{r}}
    Quote Originally Posted by Rheanna View Post
    top one is r square 2-1/r
    bottom one is r-1/r
    You mean like this:

    \dfrac{r-\dfrac{r^2-1}{r}}{1-\dfrac{r-1}{r}}
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Junior Member Rheanna's Avatar
    Joined
    Nov 2008
    Posts
    36
    Awards
    1
    yes
    Follow Math Help Forum on Facebook and Google+

  6. #6
    A riddle wrapped in an enigma
    masters's Avatar
    Joined
    Jan 2008
    From
    Big Stone Gap, Virginia
    Posts
    2,551
    Thanks
    12
    Awards
    1
    Quote Originally Posted by masters View Post
    You mean like this:

    \dfrac{r-\dfrac{r^2-1}{r}}{1-\dfrac{r-1}{r}}
    Alrighty then,

    \dfrac{r-\dfrac{r^2-1}{r}}{1-\dfrac{r-1}{r}}=\dfrac{\dfrac{r^2-(r^2-1)}{r}}{\dfrac{r-(r-1)}{r}}=\dfrac{\dfrac{r^2-r^2+1}{r}}{\dfrac{r-r+1}{r}}=\dfrac{\dfrac{1}{r}}{\dfrac{1}{r}}=1
    Follow Math Help Forum on Facebook and Google+

  7. #7
    Junior Member Rheanna's Avatar
    Joined
    Nov 2008
    Posts
    36
    Awards
    1
    lol, even staring at the problem i'm still lost.
    Follow Math Help Forum on Facebook and Google+

  8. #8
    A riddle wrapped in an enigma
    masters's Avatar
    Joined
    Jan 2008
    From
    Big Stone Gap, Virginia
    Posts
    2,551
    Thanks
    12
    Awards
    1
    Quote Originally Posted by masters View Post
    Alrighty then,

    \dfrac{r-\dfrac{r^2-1}{r}}{1-\dfrac{r-1}{r}}=\dfrac{\dfrac{r^2-(r^2-1)}{r}}{\dfrac{r-(r-1)}{r}}=\dfrac{\dfrac{r^2-r^2+1}{r}}{\dfrac{r-r+1}{r}}=\dfrac{\dfrac{1}{r}}{\dfrac{1}{r}}=1
    Let me do it another way. See if this helps.

    Multiply numerator and denominator by r.

    \dfrac{r-\dfrac{r^2-1}{r}}{1-\dfrac{r-1}{r}}

    \dfrac{r\left(r-\dfrac{r^2-1}{r}\right)}{r\left(1-\dfrac{r-1}{r}\right)}=\dfrac{r^2-r^2+1}{r-r+1}=\frac{1}{1}=1
    Follow Math Help Forum on Facebook and Google+

  9. #9
    Junior Member Rheanna's Avatar
    Joined
    Nov 2008
    Posts
    36
    Awards
    1
    yeah that r square was confusing me. ugh I know I got 0 on this pre test and Thursday is the test test.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Rational Expressions
    Posted in the Algebra Forum
    Replies: 2
    Last Post: November 11th 2010, 08:33 PM
  2. Rational Expressions
    Posted in the Algebra Forum
    Replies: 5
    Last Post: October 23rd 2010, 04:27 PM
  3. Rational Expressions and Radical Expressions
    Posted in the Algebra Forum
    Replies: 16
    Last Post: July 9th 2009, 10:29 PM
  4. Rational expressions
    Posted in the Algebra Forum
    Replies: 1
    Last Post: December 5th 2007, 09:23 PM
  5. Rational Expressions- NEED HELP PLZ
    Posted in the Algebra Forum
    Replies: 9
    Last Post: March 1st 2007, 06:48 PM

Search Tags


/mathhelpforum @mathhelpforum