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Dr. Mathva's user avatar
Dr. Mathva's user avatar
Dr. Mathva's user avatar
Dr. Mathva
  • Member for 5 years, 8 months
  • Last seen this week
  • Paris, France
47 votes
Accepted

Japanese Temple Problem From 1844

17 votes
Accepted

Proving $abcd+3\geq a+b+c+d$

15 votes
Accepted

Pigeonhole Principle Problem

12 votes
Accepted

Solution of this Diophantine Equation

8 votes
Accepted

Find all three digit numbers which are divisible by groups of its digits

8 votes

Prove that $\sum_{1\le i<j\le n}\frac{x_ix_j}{(1-x_i)(1-x_j)} \le \frac{n(n-1)}{2(2n-1)^2}$

7 votes

How we can find the sum of all roots for $x^2+\cos x=2019$

7 votes

Greatest integer less than or equal to $\sum_{n=1}^{9999}\frac{1}{n^{1/4}}$

7 votes
Accepted

For $X_{n+1}=X_n+1/X_n$ with $ X_1=1 $, prove that $X_{100}>14$.

7 votes
Accepted

Prime numbers $p<q<r$ such that $r^2-q^2-p^2$ is a perfect square.

7 votes

Equilateral triangle with vertices on 3 concentric circles

7 votes
Accepted

Overlapping circles covering polygon

6 votes
Accepted

Find the $\angle ACB$ of $\triangle ABC$.

6 votes
Accepted

Point $X$ is on the circumference of the circle $PQR$ and $PY$ is a perpendicular on $XR$. Finding the value of $QX + XR$

6 votes
Accepted

Are there coprime integers $x,y$ ( greater than 1 in absolute value) such that $3y(4x^3-y^3)$ is a square?

6 votes
Accepted

System of equations: $3^x + 4^x + 5^x = 2^x \cdot 3^{x -1} \cdot y$

6 votes
Accepted

Proof of $\sum_{n=1}^\infty a_nb_n^2c_n^3<\infty$.

5 votes
Accepted

The center of the circumcircle lies on a side of a triangle

5 votes

$x^2+xy+xz+yz=6+2\sqrt{5}$. Find the minimum of $3x+y+2z$

5 votes

Solve this: $\frac{1}{n}+\frac{1}{n+1}+\frac{1}{n+2}+...+\frac{1}{2n}>\frac{2}{3}$; without induction

5 votes
Accepted

Proof that $2(a^4+b^4+c^4)<(a^2+b^2+c^2)^2$ if and only if line segments of length $a$,$b$ and $c$ form a triangle

5 votes

How many tickets should Paul buy?

5 votes

Find the maximum value of $x(9\sqrt{1+x^2}​+13\sqrt{1-x^2​})​$

5 votes
Accepted

Inverse Fermat's theorem

5 votes
Accepted

Introduction to Geometry Books

4 votes
Accepted

Counting of natural numbers that have certain properties

4 votes

Proofs of the Weitzenbock inequality: $a^2+b^2+c^2\geq 4 \sqrt{3}\cdot(\text{area of }\triangle ABC)$

4 votes
Accepted

What is the value of $a+b$ where the area of the square in the diagram is $\dfrac{a}{b}$ and both are co-primes?

4 votes

Painting the plane, and finding points one unit apart

4 votes
Accepted

Is it possible for a square root function,f(x), to map to a finite number of integers for all x in domain of f?

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