1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Maths proof for fractions

  1. Sep 18, 2012 #1
    Could someone show me the proof to why we use the reciprocal in fractions division. I ask this because it seem we are taught the how in math but never the why. Algebra proof would be best thanks.
     
  2. jcsd
  3. Sep 18, 2012 #2
    It's not a proof, it's a definition. Division is the inverse operation of multiplication, and so dividing by a fraction is the same as multiplying by the inverse of that fraction, which is its reciprocal.
     
  4. Sep 18, 2012 #3
    My LaTeX always looks so ugly.

    [tex]n = \frac{(\frac{a}{b})}{(\frac{c}{d})}[/tex]
    [tex]n\left(\frac{c}{d}\right) = \frac{a}{b}[/tex]
    [tex]nc = \frac{ad}{b}[/tex]
    [tex]n = \frac{ad}{bc} = \left(\frac{a}{b}\right) \times \left(\frac{d}{c}\right)[/tex]
     
  5. Sep 19, 2012 #4
    Thanks for the proof abacus, well appreciated makes things clearer for me.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Maths proof for fractions
  1. Maths proofs? (Replies: 16)

  2. Math proofs (Replies: 4)

  3. Math proof (Replies: 4)

Loading...