Recent content by Jyupiter

  1. J

    Just a quick question on the identity matrix

    I'm sorry for being unclear in my previous reply. What I meant by "self-swapping" is replacing a row in a matrix by itself, e.g. Row 2 swaps with Row 2. I have no idea what determinants are yet, but perhaps its because of this that "self-swapping" is not allowed? As you could always arbitrarily...
  2. J

    Just a quick question on the identity matrix

    Thanks for the quick reply! What you said made sense. About the self-swapping row operation though, Hefferon's text stated that it's not allowed (said it has something to do with determinants later; I'm not that far into LA yet!). Is that restriction not the convention?
  3. J

    Just a quick question on the identity matrix

    I'm just wondering, is an identity matrix, say I3 considered as an elementary matrix? It's obviously possible, since we can multiply any row of I with a constant 1. I'm just curious if there is a restriction for rescaling with a constant 1.
  4. J

    Cauchy functions problem for Calculus II

    Lecturer revealed the solution: \hat{\beta}_k=arg\ max_\beta\ \prod_{i=1}^{N}\ \frac{1}{k^{2}+(x_{i}-\beta)^{2}} \Rightarrow \hat{\beta}_k=arg\ min_\beta\ \prod_{i=1}^{N}\ k^{2}+(x_{i}-\beta)^{2} \Rightarrow \hat{\beta}_k=arg\ min_\beta\ \sum_{i=1}^{N}\ ln\ (k^{2}+(x_{i}-\beta)^{2}) let...
  5. J

    Limit Test on Series: Summation from n=0 to Infinity of n!/1000^n

    Sure, why not? Do you think n!>1000^{n} for some large n to be true? If so, could you manipulate the rational function using this knowledge?
  6. J

    Cauchy functions problem for Calculus II

    Correct me if I'm wrong, but the figure attached seems to hint at K=max\ \{ (\frac{k}{\pi})^{N}\ \prod_{i=1}^{N}\ \frac{1}{k^2+(x_{i}-\beta)^2}\}. Then x_{i}\rightarrow\beta\ \Rightarrow K=(\frac{1}{k\pi})^{N}\ \Rightarrow k^{N}\propto \frac{1}{K} and k\not = 0. (I'm sure this is flawed; surely...
  7. J

    Cauchy functions problem for Calculus II

    Major Update! So I've spotted an error in the question, namely (2), which states k as a constant and a variable at the same time. I've reconciled this with my lecturer and it's confirmed that there's a misprint in the equation. (2) should actually look like this: \hat{\beta}_{k}=arg\...
  8. J

    Cauchy functions problem for Calculus II

    The complete question reads like this: "Describe the effect of k on (2) corresponding to (1). The function in (2) can be read as the values of β that would maximize the function in (1) or argument that would maximize (1)." There's an accompanying image...
  9. J

    Cauchy functions problem for Calculus II

    So I've apparently been given an assignment on Cauchy functions (it says here on the title), but I have no idea what that means. Nevertheless, here's my attempt to solve this problem: Given (1): f(x)=\frac{k}{\pi}\times\frac{1}{k^{2}+(x-\beta)^{2}} and (2): \hat{\beta}_{k}=arg\ max_{\beta}...
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