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!

Complex fraction in numerator help?

Tags:
  1. Jan 14, 2015 #1
    1. Evaluate the limit http://www4a.wolframalpha.com/Calculate/MSP/MSP64511d2754i3f4iaefab00001fa62g875680a1ia?MSPStoreType=image/gif&s=44&w=125.&h=45. [Broken]
    2. No formulas
    3.The answer is -1/9. I have tried multiplying the top by the conjugate but that seems wrong as there are no square roots involved. I just tried making numerator (not sure what that process is called where you multiply the numerator by the other fractions denominator and so on.......) into (3-3+h)/(3+h*3) all over h, but that isn't working.
     
    Last edited by a moderator: May 7, 2017
  2. jcsd
  3. Jan 14, 2015 #2

    epenguin

    User Avatar
    Homework Helper
    Gold Member

    Do what you do in elementary arithmetic when you subtract one fraction from another!
     
    Last edited by a moderator: May 7, 2017
  4. Jan 14, 2015 #3

    HallsofIvy

    User Avatar
    Staff Emeritus
    Science Advisor

    The first thing you should do is the subtraction [itex]\frac{1}{3+ h}- \frac{1}{3}[/itex]
     
  5. Jan 15, 2015 #4
    1/3+h - 1/3 --> (3-(3+h))/(3*(3+h))-->h/(3(3+h)) :( ?
     
  6. Jan 15, 2015 #5
    What happened to the negative sign on h? Also, you dropped an h from the denominator
     
  7. Jan 15, 2015 #6
    I guess it should be distributed after I multiplied by the LCD?

    Then I would have -h/(3(3+h)) --> -h/(3(3+h)) *1/h --> -1/(3(3+h)--> -1/(9+0)--> -1/9
     
  8. Jan 16, 2015 #7

    epenguin

    User Avatar
    Homework Helper
    Gold Member

    You have got the right idea, calculation and result now.
    If this is homework you are only nearly there - write this fairly short calculation up according to the pattern of argument you must have been taught or illustrated I.e. this gets by us because 'we know what you mean'.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted