1. Not finding help here? Sign up for a free 30min 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!

Differential Calculus - Question

  1. Oct 17, 2011 #1
    1. The problem statement, all variables and given/known data

    I don't understand how this can be written like this:

    [tex]\frac{1}{(2x+1)^{1/2}}-\frac{1}{(2x+1)^{3/2}}=\frac{2x+1-1}{(2x+1)^{3/2}}=\frac{2x}{(2x+1)^{3/2}}[/tex]


    What's the rule which makes this possible and explain please.
     
  2. jcsd
  3. Oct 17, 2011 #2

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    The "rule" is one that you probably learned in the third grade: you add or subtract fractions by getting a "common denominator".

    The first fraction has denominator [itex](2x+1)^{1/2}[/itex]. The second fraction has denominator [itex](2x+ 1)^{3/2}= (2x+1)^{1+ 1/2}= (2x+1)(2x+1)^{1/2}[/itex].

    In other words, the common denominator is [itex](2x+1)^{3/2}[/itex] and you get it by multiplying the numerator and denominator of the first fraction by 2x+1.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Differential Calculus - Question
  1. Differential Calculus (Replies: 10)

  2. Differential calculus (Replies: 2)

Loading...