1,403 reputation
214
bio website kmlinux.fjfi.cvut.cz/…
location Prague, Czech Republic
age 27
visits member for 1 year, 9 months
seen Jun 27 at 8:08

Math PhD student at Czech Technical University in Prague and at LIAFA in Paris.

Code licence details applicable on my posts on TeX.SX.


Oct
31
comment Find the number of positive integers whose digits add up to 42
Ok, then I probably miss a concept of "an answer" :-/ Because this is not an answer to the problem :-/
Oct
31
comment Find the number of positive integers whose digits add up to 42
Ok, I probably get your point. Maybe it should be tagged homework then?
Oct
31
suggested suggested edit on Deriving $\neg R$ from $\{R↔(R∨(P∧¬P)), R↔¬P, ¬P→(P↔(Q→Q)), P→Q\}$
Oct
31
comment Find the number of positive integers whose digits add up to 42
This is a pretty incomplete answer.
Oct
31
revised Find the number of positive integers whose digits add up to 42
added 27 characters in body
Oct
31
revised Find the number of positive integers whose digits add up to 42
added 539 characters in body
Oct
31
answered Find the number of positive integers whose digits add up to 42
Oct
31
comment If a sequence $\{S_n\}$ converges to a constant $s$, then the sequence $\{S_n^k\}$ converges to $s^k$
@akeenlogician The RHS converges to $0\cdot k(|x|+0)^k = 0$. Then apply the sandwich theorem and you get that $|s_n^k-s^k|$ converges to $0$, which is what you want.
Oct
31
answered If a sequence $\{S_n\}$ converges to a constant $s$, then the sequence $\{S_n^k\}$ converges to $s^k$
Oct
31
comment How can i use the fact that $2^{6600} \equiv 1\pmod {6601}$ to prove $6601$ fails Miller's test?
Which Miller's test do you mean? The proved-to-be-correct Rabin-Miller test or something different?
Oct
31
comment Proof that the Trace of a Matrix is the sum of its Eigenvalues
Btw, this is not more advanced than Ted's proof. This is exactly the same, just each of the steps is written out.
Oct
31
comment Proof that the Trace of a Matrix is the sum of its Eigenvalues
@Ioannis Sorry, but there's no more elementary proof than the one I and Ted provided. And I don't think I'm able to divide it into more elementary steps than I did here. Therefore I think that you can't be helped.
Oct
30
answered Proof that the Trace of a Matrix is the sum of its Eigenvalues
Oct
30
comment Proof that the Trace of a Matrix is the sum of its Eigenvalues
@Ioannis Well, if you're not able to see how you arrive to coefficient in the general case from writing down the cases $n=2,3$, then the only possiblity is to give you a very technical proof by definition. Is that what you seek?
Oct
28
answered help with summation index
Oct
28
comment help with summation index
Do you claim the two things should be equal? Because they are not, for $n=2$ you have $6a_0+32a_0+32a_1\neq6a_0+6a_0+8a_1$, if I computed it correctly. What exactly do you want?
Oct
20
comment Maclaurin series for $e^z /\cos z$.
The explanation of the convergence radius is rigorous :) Usually when you compute first 4 or 5 coefficients by derivatives, you get the idea as what the formula for them is and then proving it works is usually quite simple.
Oct
20
comment Positive definiteness of matrix?
@VedranŠego I would say that this is a minor nuance in terminology. Anyways, it certainly doesn't really help here since it's easier to prove the correct statement from definition than using Sylvester.
Oct
20
comment Positive definiteness of matrix?
Sylvester's theorem is a common term in some countries, and its statement is: Let $\Delta_i$ be the leading minors. Then $A$ is PD iff $\Delta_i>0 \ \forall i$ and is ND iff $(-1)^i\Delta_i>0\ \forall i$.
Oct
19
revised finding the inverse of function. the domain is given and the question requires to find the inverse.
corrected markup