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!

Transform formula into another form

  1. Feb 4, 2017 #1
    1. The problem statement, all variables and given/known data
    I need help when changing the formula of the yellow circled part to red-circled part ...

    2. Relevant equations


    3. The attempt at a solution
    I tried , but i didnt get what the author got .... Here's my working ... Which part of my working is wrong ?
     

    Attached Files:

    • 26.JPG
      26.JPG
      File size:
      48.4 KB
      Views:
      36
    • 27.jpg
      27.jpg
      File size:
      28.2 KB
      Views:
      33
  2. jcsd
  3. Feb 4, 2017 #2

    Mark44

    Staff: Mentor

    Moved to Calculus and Beyond section.
    @fonseh, many helpers won't respond if the problem statement and work are shown only in attached images.
     
  4. Feb 4, 2017 #3

    haruspex

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    I cannot make sense of the text either. It looks quite wrong. Certainly a du has been omitted from the right hand side, and I cannot see how that 1-u term can appear. Perhaps the N exponent is in the wrong place. Maybe some approximation has been made, but that should be stated.
    Your own working has y on the right instead of dy (=y0du).
     
  5. Feb 4, 2017 #4

    haruspex

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    2016 Award

    The closest I can get is ##\frac{y_0du}{S_0}[\left(1-\frac {1}{1-u^N}\right)## ##(1-(\frac{y_c}{y_0})^Mu^{-M})^{-1}]##.
    If we use the binomial approximation for the last (...)-1 term, we get:
    ##\frac{y_0du}{S_0}[\left(1-\frac {1}{1-u^N}\right)## ##(1+(\frac{y_c}{y_0})^Mu^{-M})]##.
    Multiplying the brackets out produces something quite close to the text. The remaining differences look like typos.
     
  6. Feb 6, 2017 #5
    Can you show your working pls ? I tried it many times , but didnt get the red part , i gt (1-(1/u)^N ) instead
     
  7. Feb 6, 2017 #6
    This is actually hydraulic formula , should i move it to another thread ? Or this is just purely mathematics derivation ? I'm not sure
     
  8. Feb 7, 2017 #7

    Mark44

    Staff: Mentor

    It's fine here. The gist of the question is mathematical in nature.
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Transform formula into another form
Loading...