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Oscar Lanzi
  • Member for 7 years
  • Last seen this week
67 votes

Is the "determinant" that shows up accidental?

63 votes

Are rational points dense on every circle in the coordinate plane?

37 votes
Accepted

Alternating series; first term is 0. Do I have a problem?

35 votes

Is the arc length always irrational between two rational points?

33 votes

Multiple-choice: sum of primes below $1000$

30 votes
Accepted

Why does the circle intersect the line?

26 votes

What problems have been frequently computationally verified for large values?

25 votes

Best approximation of log 3?

21 votes
Accepted

How to solve this solvable 8th-degree algebraic equation by radicals?

20 votes
Accepted

Is there an easy way to see that ${1\over5} + \frac{1}{6} + \frac{1}{7} + \frac{1}{8} + \frac{1}{9} + \frac{1}{10} + \frac{1}{11} + \frac{1}{12} > 1$?

17 votes
Accepted

An algebraic riddle: The king's chest full of bags of gold coins

16 votes

Is there a surface on which a hexagon can have all right angles?

14 votes
Accepted

Is there a proof that doubling the sum of squares of any two integers will always equate to another sum of two squares?

14 votes

Unexpected examples of natural logarithm

14 votes

Is the catenary the trajectory of anything?

13 votes
Accepted

$\tan(z)=i$, no solution

12 votes

Prove that $23$ does not divide $2^n + 3^m$, for any $m, n \in \mathbb{N}$

12 votes

How can a mug and a torus be equivalent if the mug is chiral?

11 votes

Why doesn't $\int\lfloor {x}\rfloor~dx=x\lfloor x\rfloor +C$?

11 votes

Help with $\int _0^{\infty }\frac{\sinh \left(x\right)}{x\cosh ^2\left(x\right)}\:\mathrm{d}x$

11 votes
Accepted

Showing that $4b^2+4b = a^2+a$ has no non-zero integer solutions?

10 votes

Why is the "solving for cubic equation roots general rule" sometimes not applicable while the equation obviously has roots?

10 votes

Prove the following trigonometric identity without a calculator involved

9 votes

Happy $\pi$-day! Is it true that $\sum_{p \;\text{prime} } \frac{1}{{\pi}^p} < \pi -\lfloor \pi \rfloor$?

9 votes

$6!\cdot 7!=10!$. Is there a natural bijection between $S_6\times S_7$ and $S_{10}$?

9 votes
Accepted

prove that $X^2 \equiv 35 \pmod{100}$ has no solutions

9 votes

How to solve the differential equation $xx'' = (x')^2$?

8 votes

A possible solution to $\sqrt {5-x}=5-x^2$ (without taking square from both sides)

8 votes
Accepted

Simple continued fraction of $\sqrt{d}$ with period of shortest length $3$

8 votes
Accepted

What is the smallest possible value of $q$ such that $\frac{7}{10}<\frac{p}{q}<\frac{11}{15}$?

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