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Confused about one equation

  1. May 20, 2013 #1
    The explanation for this is probably very trivial, but I am not seeing it. I'm reading through Ramamurti's "Basic Training in Mathematics" and in the Multivariable Calculus section for spherical coordinates he says

    and then shows an integral. Shouldn't there be a negative sign before the cosθ? And how is this equal to dz?

    Thanks in advance
  2. jcsd
  3. May 20, 2013 #2


    Staff: Mentor

    Yes, there should be a minus sign.
    Apparently things started with this:

    z = cosθ
    dz = d(cosθ) = -sinθ dθ

    It looks to me like the author is doing an ordinary substitution (z = cosθ) before carrying out the integration.
  4. May 20, 2013 #3
    Ah, I see. Thanks for the quick response!
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