Recent content by cqfd

  1. cqfd

    Integrating sin(x)*cos(x) paradox

    Oh, ok. So there's just a constant offset between the two solutions that we do not care about. :)
  2. cqfd

    Integrating sin(x)*cos(x) paradox

    I am encountering a paradox when calculating the integral ##\int sin(x)\cos(x)\,dx## with integration by parts: Defining ##u = sin(x), v' = cos(x)##: ##\int sin(x)cos(x) dx = sin^2(x) - \int cos(x) sin(x) dx## ##\Leftrightarrow \int sin(x) * cos(x) dx = +1/2*sin^2(x)##. On the other hand...
  3. cqfd

    What is the RMS deviation from the true mean for a Gaussian distribution?

    I'm always a little uncertain about such notational things, so just before i start, what you mean by your concrete notation, is that the experiment is performed 2 times, each times taking a sample of size N. In that case, the distribution of the position is given by the product of the total...
  4. cqfd

    What is the RMS deviation from the true mean for a Gaussian distribution?

    Sorry, i first thought i wanted to add something, but it ended up being wrong. :/ So this post can be deleted.
  5. cqfd

    What is the RMS deviation from the true mean for a Gaussian distribution?

    Oh, ok i see what you mean. I should have stated it like in post #9 from the beginning. ^^ Now I've thought about the RMS part some more, but i can't get my head around it. Has it something to do with this property? Because then we would have ##RMS(X_1+X_2+...+X_N) =...
  6. cqfd

    What is the RMS deviation from the true mean for a Gaussian distribution?

    But you're saying basically the same thing, and i don't understand how your way should be a valid proof, but not mine? And shouldn't the expected value for each random variable that is corresponding to a draw from the sample ##X_i## be already ##x_0##? I.e. ##\forall i \in [1,N], E[X_i] =...
  7. cqfd

    What is the RMS deviation from the true mean for a Gaussian distribution?

    I've given the problem a second try, from the beginning, thinking about what you said. Now this is what i came up with, i tried to order all the different terms, and hope you correct me if there's something wrong: We define a random variable, X, the position of the object. We know the pdf of...
  8. cqfd

    What is the RMS deviation from the true mean for a Gaussian distribution?

    Thanks for your help already. This all makes sense to me intuitively, I mean it is clear to me that when we make the measurements many times and take the mean value, that this value is going to converge to x0, but I just can't figure out how to write this down formally. And I still can't figure...
  9. cqfd

    What is the RMS deviation from the true mean for a Gaussian distribution?

    Hmm, this makes sense. In fact his was what I thought of in the first place. So I get the mean like this: <x>N = 1/N*sum(xi) I'm sorry but I don't understand what this means. All I've calculated so far are the means of the individual samples <x>N,j with the now hopefully correct formula. But...
  10. cqfd

    What is the RMS deviation from the true mean for a Gaussian distribution?

    Hi everyone, I'm new here and this is my first post in this forum. ^^ Homework Statement Suppose that you observe a fluorescent object whose true location is x0. Individual photons come from this object with apparent locations xi in an approximately Gaussian distribution about x0...
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