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rogerl
  • Member for 10 years, 3 months
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58 votes

There exists a power of 2 such that the last five digits are all 3's or 6's. Find the last 5 digits of this number

30 votes
Accepted

Does any given integer only occur in one primitive Pythagorean triple?

25 votes
Accepted

What's the difference between a bijection and an isomorphism?

22 votes
Accepted

Why is every positive integer the sum of 3 triangular numbers?

17 votes
Accepted

Generating functions and central binomial coefficient

15 votes

$ \tan 1^\circ \cdot \tan 2^\circ \cdot \tan 3^\circ \cdots \tan 89^\circ$

13 votes
Accepted

A differentiation question conceptual query

13 votes
Accepted

Counterexamples to proofs of correct statements

12 votes
Accepted

If $p$ is prime, $p\ne3$ then $p^2+2$ is composite

12 votes

How do I prove that $x^p-x+a$ is irreducible in a field with $p$ elements when $a\neq 0$?

12 votes

Probability that a number is divisible by 11

12 votes
Accepted

Find a generator of the multiplicative group of $\mathbb{Z}/23\mathbb{Z}$ as a cyclic group

11 votes
Accepted

Show that the equation $x^{4} + rx + s = 0$ has at most two distinct real roots.

11 votes

How to draw the graph of this function? (very difficult)

10 votes

How To solve This Perfect Square Word Problem

10 votes
Accepted

How to prove $2\sin^2(80^\circ) - \sin(70^\circ)=1$?

10 votes

Unusual result to the addition

9 votes
Accepted

Totient Function $\varphi{(x)}=24$

9 votes
Accepted

Prove that there is no number that divides both n and n+1

9 votes
Accepted

Methods for determining which roots of a polynomial are inside of the unit circle?

8 votes
Accepted

What is the best way to solve an equation of the form $(f(x))^2-a(f(x))+b=x$?

8 votes

Unconventional mathematics books

8 votes

How to find all Pythagorean triples containing a given number?

8 votes

Polar form of a complex number

7 votes
Accepted

Proving the number of commuting pairs of elements in $G$ equals number of conjugacy classes in $G$ times $|G|$

7 votes

Proving $x^{2}+1 \neq n! $,using Gaussian Integer.

7 votes

Proving Any connected subset of R is an Interval

7 votes

Simplify the following complex fraction:

7 votes
Accepted

Diagonalisation argument for real numbers

6 votes

How many triangular numbers have exactly $d$ divisors?

1
2 3 4 5
28