5,957 reputation
11436
bio website
location
age
visits member for 2 years, 2 months
seen 5 hours ago

Jun
30
comment does the series converge? $\sum_{n=1}^\infty\left(\frac {3}{5^n}+\frac 2n\right) $
@Joshhw I'm not sure what you mean by $a_n$. Each term of the series in your question is greater than the corresponding term in the harmonic series. If the terms in one (positive) series are greater than the terms in a divergent (positive) series, then of course the former series diverges too.
Jun
30
answered does the series converge? $\sum_{n=1}^\infty\left(\frac {3}{5^n}+\frac 2n\right) $
Jun
30
answered Number of particular terms in a product
Jun
30
comment Another mid level math question about %.
@helena4 Note that this isn't just some method that happens to work, this is what division is for. The definition of $a/b$ is "what do I need to multiply $b$ by to get $a$".
Jun
30
comment Probability of two cot deaths in one family
Would this be more appropriate for the Statistics SE?
Jun
30
answered Subtraction of a negative number
Jun
27
comment Is $\mathbb{R}^n$ a field?
@AsafKaragila Do you just have a list of what's consistent with what memorized, or do you just know enough set theory to be able to come up with arguments on the fly?
Jun
26
comment Integer values of $\frac{x}{y}+\frac{y}{z}+\frac{z}{x}$?
In other words, when is $x^2z+y^2x+z^2y$ a multiple of $xyz$?
Jun
26
answered Logic question for a program I'm designing
Jun
26
comment Logic question for a program I'm designing
I can't quite understand the problem. So you have a trailer with $10$ slots for boats in it. What does "1C/2K" mean? You can put either one canoe, or two kayaks? You say you need to determine whether or not the trailer is full - what data do you have? Just how many kayaks and canoes are currently reserved?
Jun
26
reviewed No Action Needed Compute the first six terms of the following sequences (start with n = 1):
Jun
26
comment Prove that the characteristic polynomial of a nilpotent matrix is $x^n$
I think that your complaint is that I'm being too rigid, and that we should be able to accept intuitively obvious facts as intuitively obvious without proof. What I'm saying is that if you don't know about factorization, the fact that $x^n$ is the only polynomial whose only root of $0$ isn't intuitively obvious.
Jun
26
comment Prove that the characteristic polynomial of a nilpotent matrix is $x^n$
@Mathmo123 I don't think it's acceptable at all. Maybe $x^5+6x+75x-2x$ has no roots other than the obvious root of $0$. I don't know, it's very hard to tell at a glance. You need the fact that you can split polynomials. You have to at least mention that very non-obvious fact, otherwise what you have doesn't even come close to being a proof.
Jun
25
answered Prove that the characteristic polynomial of a nilpotent matrix is $x^n$
Jun
25
comment Generalization of Liouville's theorem
I think a more natural generalization would be: does there exist a set of functions containing $E$ which is closed under composition, arithmetical operations, and anti-derivation?
Jun
25
comment another counting problem
@user157920 But you are interested in finding a formula, not necessarily a program, right?
Jun
24
comment Factorial of zero is 1. Why?
You could also say there are no ways of arranging $0$ items, because you can't arrange them. A bit like how you could argue that $x/0$ should be $x$, because you're not doing any dividing. For reasons like this, I think edge cases like this are best handled formally, rather than trying to give intuitive explanations, which tend to collapse when examined more closely.
Jun
24
comment Translate a German paper by Hilbert
@amWhy Fair enough. I assumed from your first comment that you were opposed to the question.
Jun
24
comment Translate a German paper by Hilbert
@amWhy "Go for it, then!" Don't be so ridiculous. What's your argument, here, that because one person doesn't have the time or inclination to fulfill a request, therefore that request is too demanding and shouldn't even be posted?
Jun
24
comment Translate a German paper by Hilbert
@amWhy It's five light pages. There's no harm in throwing out a request.