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Homework Help: Another change in unit vectors (d(r-hat)/d(theta)) in Cylindrical

  1. Nov 18, 2011 #1
    1. The problem statement, all variables and given/known data

    Does anyone know what d(r-hat)/d(theta) in Cylindrical coordinates is?

    2. Relevant equations

    3. The attempt at a solution

    I'm pretty sure its -(theta-hat) but I'm not sure, any help?

    Thanks so much
  2. jcsd
  3. Nov 18, 2011 #2
    so theta is moved over by d(theta) shifting over r-hat and theta-hat.. What would d(r-hat)/d(theta) be?
  4. Nov 18, 2011 #3
    anyone? :)
  5. Nov 18, 2011 #4

    I like Serena

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    Homework Helper

    Hi khfrekek1992! :smile:

    [tex]{d\hat r \over d\theta} = \hat \theta[/tex]

    If you draw [itex]\hat r[/itex] for 2 angles, you'll see that the vector-difference between them points in the direction of [itex]\hat \theta[/itex].
    Its (approximate) length is [itex]d\theta[/itex].
  6. Nov 18, 2011 #5
    Oh! I see how you get that now.. Thanks so much! That helps a ton :D
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