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seen Jul 22 at 0:17

Jul
20
comment Prove $A \subset \emptyset \iff A = \emptyset$
I gave your answer the points because it was the most thorough and points out the issues in my proof. Although, what does Git Gud mean by his comment? What is the prejudice against the statement?
Dec
20
comment Please show $|\sin(n+1)x| = |\sin(nx+x)|$
Thanks. That makes sense. Is this typically how arguments for sine are written? I feel like the way you have written in in your answer makes much more sense, in fact, aren't the extra set of brackets necessary? Otherwise what I wrote in my question should be interpreted as (sin(n+1))*x, right?
Jun
10
comment How to evaluate $ \lim_{(x,y)\to(0,0)}\frac{y^2\sin^2x}{x^4+y^4} $
Thank you, Peter!
Jun
10
comment How to evaluate $ \lim_{(x,y)\to(0,0)}\frac{y^2\sin^2x}{x^4+y^4} $
Thanks, Robert. That makes sense. So to my earlier point, is it sufficient to say that since the limit depends on the value of alpha, the limit cannot exist?
Jun
10
comment How to evaluate $ \lim_{(x,y)\to(0,0)}\frac{y^2\sin^2x}{x^4+y^4} $
Ok, I did that. I notice that the limit is dependent on the value of alpha which means the limit does not exist. Is this sufficient? Once I state this, what is the point of using sin(x)/x -> 1?
May
26
comment Find cumulative, marginal densities, moments for $f(x)=2,\le y \le x \le 1$ (multivariate)
I really appreciate you taking the time to answer as thoroughly as you did. Thanks for the help! I think that should be enough to get me started on my own for now.
May
25
comment When deriving the multivariate normal distribution, please explain this limit
Thanks for the explanation. Although, what's the point of having (1/(delta x * delta y)) in the limit? Wouldn't the difference still go to zero without it?
May
22
comment Why is the PDF of this multivariate student t model $f(l)=Cl^{m-1}e^{-l^2/2}$
Very informative, thank you.
May
21
comment How would one rescale the variance and standard deviation of a set of data?
I knew that it would be something trivial like this. Can you show why this works?
May
14
comment Sign restriction on the Lagrange multiplier? Why?
I have an idea of what you mean. Could you define gradient?
May
14
comment Does a quadratic necessarily have a root in this interval?
@Wonder Great explanation. I see there must be a root in the interval. So would this also imply that the points at F(b/a) and F(-b/a) must have different signs themselves? Or only that a sign change must exist?
Mar
9
comment Proof involving matrix inverse of: $\|A^{-1}\|_\infty \ge \frac{\|U^{-1}\|_\infty}{n}$
This is great thanks a lot! I was focusing on relating the absolute row sum of inv(A) to that of inv(U) and totally missed the property of L that completes the inequality!