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Homework Help: Silly Question Maybe?

  1. Jan 13, 2014 #1
    1. The problem statement, all variables and given/known data

    I have a very simple question I am having problems with.

    2. Relevant equations

    n= C/V

    3. The attempt at a solution

    Hey guys,

    This is a very simple equation indeed. I am a mature student and starting up in physics.
    My mathematics is terrible. So please don't laugh. I can seem to integrate and differentiate but for some reason, I have forgotten something really really really stupid.

    I rearranged the above formula earlier and to solve for v and I came up with Cn=V.

    I dont know why I am doing that and this, I had no problem before.

    So my question is, when changing sides of an equation, how do I know which to move from one side to the other and in what order.

    Do i start with numerator or denominator. And if so, what order.

    I have exams coming up and im in a divorce currently and really really simple stuff has completely slipped from my brain. For obvious reasons, I cant ask this question at my university.

    I am in a bit of a panic.
  2. jcsd
  3. Jan 13, 2014 #2
    Multiply both sides by V, and then divide both sides by n.
  4. Jan 13, 2014 #3
    Cheers, but why do you move the v first and not the C???

    Is it because its the bigger number or do you always move the denominator first and solve in more steps?
  5. Jan 13, 2014 #4
    like why wouldn't you just move the C first??!

  6. Jan 13, 2014 #5
    And say for example I am using the Snells law formula where there is a fraction on each side of the equation.
    How do I know when changing sides whether to add to the numerator or denominator? thanks.
  7. Jan 13, 2014 #6
    No worries, cross multiplication was what im looking for.

    Can you believe i made it to second year astro in the top 50 uni's in the world???!

    Jeeze... exams do funny things to you.

    Thanks mate.
    Last edited by a moderator: Apr 29, 2014
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