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!

Homework Help: This is an easy problem that I don't know why I'm having trouble with it

  1. Apr 13, 2009 #1
    1. The problem statement, all variables and given/known data
    So I've been doing some hw and I came to a problem that I'm not getting. I know it's simple math but what am I forgetting? The question is:
    (R + sL)(1/sC)

    What I did is:
    (R/sC)+(sL/sC)= (R+sL)/sC= (R+L)/C=?

    But the answer is (1/C)(s + R/L). So what did I do wrong and could you show me step by step on how to get that answer?
  2. jcsd
  3. Apr 13, 2009 #2
    You can't factor out the s like that, there is no sR term, so you shouldn't be getting (R+sL)/sC= (R+L)/C

    edit: But yes, you really should check you typed the answer/problem correctly...
    Last edited: Apr 14, 2009
  4. Apr 13, 2009 #3
    [tex]\frac{1}{sC}\left(R + sL\right)=\frac{R}{sC}+\frac{sL}{sC}=\frac{R}{sC}+\frac{L}{C}=\frac{1}{C}\left(\frac{R}{s}+L\right)[/tex]

    You need to cancel things with every term when you're simplifying fractions. And are you sure you typed the answer correctly?
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook