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Homework Help: Solve for y'

  1. Aug 14, 2009 #1
    1. The problem statement, all variables and given/known data
    Solve for y'


    2. Relevant equations

    3. The attempt at a solution

    so the ' means degrees right?
    Would you start by grouping like terms. My real question is how that ' makes the other variables change?
  2. jcsd
  3. Aug 14, 2009 #2


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    No, [tex] y' [/tex] is the first derivative of [tex] y [/tex]. You need to isolate [tex] y' [/tex] from the other variables, but I see one problem: you don't have this expression set equal to anything: as it stands you can factor it (a little), but there is no way to solve it for any of the quantities.
  4. Aug 14, 2009 #3


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    You need to be more specific. To solve for a variable you need to have an equation. What you have written down is not an equation at all so make sure you also write down the other side of the equation like so, 'what you have'=....

    Usually y' means the derivative of y. In this case I would guess with respect to x.
  5. Aug 14, 2009 #4
    sorry it is =0
  6. Aug 14, 2009 #5
    Then, factor out y' and solve the equation.
  7. Aug 14, 2009 #6


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    You mean, 2x+2xy'+2y+3y2y' = 0, and want to find y'.

    You can precisely perform steps according to:

    Commutative property of addition;
    Additive Inverse property;
    Like Terms or Reverse of Distributive Property;
    Multiplicative Inverse property.
  8. Aug 14, 2009 #7
    so y' is treated like another variable. I can do normal factoring and just treat it like it was a third variable like if it was a z instead?
  9. Aug 14, 2009 #8


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    YES, from the viewpoint of "Pre-Calculus" and any Math course below. Some variable names may have subscripts to distinguish between or among similar main symbols. The "prime" notation can also be used sometimes. You have the variable written, y', spoken as "y prime". Your example also has the variable, y. So, two of your variables in your example are y and y' ("y" and "y prime"). We assume that they share some character but that they represent different numbers.
  10. Aug 14, 2009 #9
    yes i understand now, thank you. i think i can handle the factoring.
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