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Homework Help: Confusion about how to work out the uncertainty in my final calculated value!

  1. Nov 17, 2011 #1
    1. The problem statement, all variables and given/known data
    So basically I have plotted two variables I measured on a graph, which gives a simple linear relationship, and have found the gradient and standard error of the gradient (1.21251 and 0.03275 respectively). Now my problem is that this gradient is equal to a constant divided by the value I'm trying to calculate i.e G=constant/v so when I express the variable v with its uncertainty how do I calculate this uncertainty in v from knowing the error in G?

    2. Relevant equations
    (2*pi*f)/c = G

    3. The attempt at a solution
    I attempted to find the ratio between the standard error of the gradient and the gradient and then multiply by my value for c, i.e 0.02042/0.03275*c, is this the correct method?
  2. jcsd
  3. Nov 17, 2011 #2
    If i'm reading your questions right.

    [Δv/v]2 = [ΔG/G]2

    [δG/δv]2/G(v)2 = [ΔG/G]2

    bascially you want to take the partial derivative of your function G= constant/v and square it then divide the entire thing by G2

    then solve for ΔG which should be ΔG = [GΔv]/v

    I can't name the function, if this is for a lab, i'm hoping your school puts the error functions in the manual.
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