Recent content by mag487

  1. M

    Uniqueness of Laplace Transform

    Right, but I didn't entirely understand how this pertained to the question of whether \int_{0}^{\infty}x^{n}f(x)\mathrm dx = 0 for each integer n >= 0 implies that f(x) = 0 for x nonnegative (which is what my attempted proof used, perhaps incorrectly referring to those integrals as "moments")...
  2. M

    Uniqueness of Laplace Transform

    Thanks, but I'm not sure I understand. I'm looking at the integral from 0 to infinity of x^n*f(x). In this case, it would be \int_{0}^{\infty}x^{n}e^{\frac{-1}{x^{2}}} \mathrm dx , which is infinite for each n rather than 0. I realize now that I may have been misusing the term "moment;" I was...
  3. M

    Uniqueness of Laplace Transform

    Hello, I was trying to prove that the Laplace transform is unique and was wondering if anyone could tell me if I've made any errors in my attempt. Here it is: Suppose L(f) = L(g), where L() denotes the Laplace transform. We want to show that f = g. By linearity of the transform, L(f - g) = 0...
  4. M

    Limits of infinite sums of sequences

    O.K., here's an easy counterexample to the general claim: \displaystyle \sum_{i=1}^{\infty} \lim_{n\rightarrow\infty} \frac{1}{2^{n}} = 0, \ \lim_{n\rightarrow\infty} \sum_{i=1}^{\infty} \frac{1}{2^{n}} = \infty. Limits usually behave so naturally in terms of commuting with other...
  5. M

    Limits of infinite sums of sequences

    I understand that the limit of the sum of two sequences equals the sum of the sequences' limis: \displaysyle \lim_{n\rightarrow\infty} (a_{n} + b_{n}) = \lim_{n\rightarrow\infty}a_{n} + \lim_{n\rightarrow\infty}b_{n}. Similar results consequenly hold for sums of three sequences, four sequences...
  6. M

    Is an Uncountable Probability Space with a Full Power Set Sigma-Algebra Viable?

    Hi, I'm new here. I'm trying to teach myself measure theory and probability and recently wanted to find an example of a probability space (X, A, P) where X is uncountable and the sigma-algebra A is the entire power set of X. Here was my idea: let X be the set of all strings c1c2c3... for c_{i}...
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