Results 1 to 3 of 3

Math Help - Help me understand why p over q over...

  1. #1
    Newbie
    Joined
    Feb 2006
    Posts
    16

    Help me understand why p over q over...

    Hello.

    I'm currently going through I.M Gelfand and A. Shen's "Algebra".
    The section I'm on is about converting rational expressions to quotients of two polynomials.

    The book shows how to do the transformations.

    e.g.

    \frac{P}{Q} + \frac{R}{S} = \frac{PS}{QS} + \frac{QR}{QS} = \frac{PS + QR}{QS} where P,Q,R and S are polynomials. That I understand.

    All make sense to me but the last which is for division:

    \frac{P}{Q} / \frac{R}{S} = \frac{PS}{QR}

    Can anyone explain why that is so? Or do I just need to work on dealing with fractions?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member topher0805's Avatar
    Joined
    Jan 2008
    From
    Vancouver
    Posts
    336
    When dividing fractions, flip and multiply.

    So, \frac {P}{Q} /\frac {R}{S} becomes \frac {P}{Q} \cdot \frac {S}{R}
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Feb 2006
    Posts
    16
    That's right! Not sure how I managed to forget that. Slightly embarrassing really. Thanks so much for the speedy reply as well.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 5
    Last Post: May 30th 2010, 02:36 PM
  2. Replies: 0
    Last Post: February 27th 2010, 11:57 AM
  3. Don't really understand
    Posted in the Math Topics Forum
    Replies: 3
    Last Post: September 23rd 2008, 07:34 PM
  4. P&C qns: Please help me understand
    Posted in the Statistics Forum
    Replies: 3
    Last Post: February 20th 2008, 03:31 AM
  5. Help me understand this please!!
    Posted in the Algebra Forum
    Replies: 2
    Last Post: September 30th 2007, 11:41 AM

Search Tags


/mathhelpforum @mathhelpforum