Derek Luna's user avatar
Derek Luna's user avatar
Derek Luna's user avatar
Derek Luna
  • Member for 5 years, 10 months
  • Last seen more than a week ago
5 votes

Inequality proof by induction

5 votes
Accepted

If $A$ and $B$ are sets, do $\mathcal{P}(A - B)$ and $\mathcal{P}(A) - \mathcal{P}(B)$ equal?

4 votes
Accepted

Find all the integer solutions of $x^2-4y^2=1$

4 votes
Accepted

If the square of an irrational number r is irrational, can it be equal to a + br, where both a and b are rational

4 votes

How to prove that, if two numbers are equal $\mod2$ and$\mod3$ ,they are equal$\mod 6 $?

3 votes
Accepted

construct a sequence Sn that does not converge but its arithmetic mean converges to 0

3 votes

Why is my solution wrong to $\,99x \equiv 18 \mod 30$

3 votes
Accepted

What is the connection between number of permutations and number of subsets?

3 votes
Accepted

(2n + 1) + (2n) is odd?

3 votes
Accepted

Prove that all members of a recursive sequence are coprime

3 votes

How to verify if vectors of $\mathbb{R}^{2 \times 2}$ span $\mathbb{R}^{2 \times 2}$

2 votes

When dealing with a group, is it possible that we have $\forall _{a\in G}\:\:a^{-1}=fixed$ (and no "individual" invertible elements?)

2 votes

Proof of $(ab)^{-1} = a^{-1}b^{-1}$

2 votes
Accepted

Proving that $\gcd(a,ak+c)=\gcd(a,c)$

2 votes

Prove that Dirichlet function is non monotonic.

2 votes

Prove prime number p divides 1+...+n^{p-2}

2 votes

Find the function p(x)

2 votes
Accepted

Let $(G,*)$ be an abelian group. Prove that, for all $a,b \in G$, then $(ab)^n = a^nb^n$ for three consecutive integers $n$.

2 votes
Accepted

Minimal value of a diophantine expression

2 votes
Accepted

Disproving that $\mathbb N$ is a complete Set

2 votes

Cannot find limit using epsilon delta definition

2 votes
Accepted

probability of selecting two roses of different colors when two roses are drawn at random from $2$ red roses, $4$ yellow roses and $6$ pink roses

2 votes
Accepted

Solve this logic problem, or justify why it can't be solved?

2 votes

Proving a sequence has a finite Limit

2 votes
Accepted

If $\gcd (a,n) = 1$, how can we prove that $\gcd(a + kn, n) = 1$?

2 votes
Accepted

Show that 2020 divides $p\left( n \right)$ for every integer $n$

2 votes
Accepted

Show that $4\mid f_n$ if and only if $6\mid n$.

2 votes
Accepted

How do you find a defined relation?

2 votes
Accepted

Why are permutations defined as bijective?

2 votes

Proposition: Al knows only Bill

1
2 3 4 5 6