user avatar
user avatar
user avatar
Francisco José Letterio
  • Member for 4 years, 9 months
  • Last seen this week
  • Buenos Aires, Argentina
41 votes
2 answers
3k views

Do you lose solutions when differentiating to solve an integral equation?

29 votes
5 answers
4k views

Why must be the additive and multiplicative identities in a field be different?

6 votes
1 answer
441 views

Help proving that a polynomial has n roots and that they're all different

5 votes
1 answer
93 views

Whst's the relationship between these two theorems? [duplicate]

4 votes
0 answers
58 views

Counting all $9 \times 8$ matrices with two restrictions (checking if I'm right)

3 votes
2 answers
132 views

Is there an intuitive way of thinking why a rearranged conditionally convergent series yields different results?

3 votes
1 answer
69 views

Let$A$ be an open, dense set in $\mathbb R^n$. Prove that $A + A = \mathbb R^n$

3 votes
1 answer
38 views

Prove that given a finite set $A$ in the plane, there is an infinite family of points that have the same distance ($d_{\infty}$) to each point in A

3 votes
1 answer
521 views

Why does this identity hold for Fejér Kernels?

3 votes
2 answers
147 views

Let X be a set with 30 elements. How many equivalence relations can be defined on X if every class of the relation must have exactly 6 elements?

2 votes
2 answers
94 views

Finding the limit as x approaches 1 of $\sum \frac {(-1)^{n+1}}{n} x^n$

2 votes
1 answer
41 views

How to prove $x^2f -(x+1)f' = x^2g -(x+1)g' \Rightarrow f = g$ for polynomials f,g with rational coefficients

2 votes
1 answer
39 views

How to find a Graph's $K_v$?

2 votes
4 answers
1k views

How to better prove this statement? Let G be a graph with $n$ vertices and $k > {n-1 \choose 2}$ edges. Then G is connected

2 votes
1 answer
527 views

What are the eigenvectors of a recurrence relation?

2 votes
0 answers
42 views

Is there any way to predict the amount of "carries" one could get by doing a sum?

2 votes
0 answers
366 views

Proving this Legendre's Formula [duplicate]

1 vote
0 answers
53 views

Prove that the sum of digits of n, when n is written in base 2, is equal to the sum of digits of 2n

1 vote
3 answers
113 views

Solve $\begin{cases}8x^{329} + 6x^{628} -2 \equiv 1 \pmod {15}\\(x^{1328} - 4)^2 \equiv 0 \pmod 7\end{cases}$ .

1 vote
2 answers
631 views

Prove that the following polynomial has no multiple roots [duplicate]

1 vote
1 answer
29 views

Distributing 10 different folders between 7 people such that John gets at least 1 folder

1 vote
1 answer
1k views

How many ways are there to park cars and motorcycles in a parking lot with 100 spaces?

1 vote
1 answer
129 views

Is my reasoning correct? (using the stars and bars method)

1 vote
2 answers
102 views

Proving that the limit at $(0,-1)$ does not exist

1 vote
1 answer
73 views

Help with identity proof using sum manipulations

1 vote
0 answers
41 views

Can we find a solution for this indefinite sum using finite calculus?

1 vote
0 answers
66 views

Help identifying mistake during sum manipulation

1 vote
2 answers
183 views

Prove that for a sufficiently differentiable $f$, if $f(x,y) = g(x+y)$ then its partial derivatives are equal

1 vote
0 answers
68 views

Is there a name for this notion in mathematics?

1 vote
1 answer
48 views

Which of these two definitions is wrong?