Intereting Posts

Prove that $f(x)=d(x,A)=\inf_{y\in A}d(x,y)$ is continuous on $M$
Why determinant of a 2 by 2 matrix is the area of a parallelogram?
Computing the order of elements in Dihedral Groups
Find eigenspace for eigenvalues of a linear transformation $T(M)=-2M^t+M$
Antisymmetric Relations
Does the existence of $\mathop {\lim }\limits_{x \to + \infty } \frac{{f(x)}}{x}$ always imply the existence of asymptote?
Minimum size of largest Clique in a Graph
half-derivative of $x^2$
Calculate the tensor product of two vectors
Constructing arithmetic progressions
Exact power of $p$ that divides the discriminant of an algebraic number field
Computing: $\lim\limits_{n\to\infty}\left(\prod\limits_{k=1}^{n} \binom{n}{k}\right)^\frac{1}{n}$
Continuous function $f:\mathbb{R}\to\mathbb{R}$ such that $f(f(x)) = -x$?
Fibonacci Numbers Proof
Does there exist a bijective $f:\mathbb{N} \to \mathbb{N}$ such that $\sum f(n)/n^2$ converges?

Ok, so this question is from seriously hard IQ test that has been doing the rounds on facebook, ok, 17 questions are easy 3 are hellishly hard, The answer to this one is 17, I do not know why, I found out by trial and error just to test, but It’s killing me, anyone know why?

- Closed form for $ S(m) = \sum_{n=1}^\infty \frac{2^n \cdot n^m}{\binom{2n}n} $ for integer $m$?
- How to solve this sequence $165,195,255,285,345,x$
- Summation of series 12,40,90,168,280,432,…?
- Formula to this pattern?
- What is the next picture in this sequence?
- Palindromic Numbers - Pattern “inside” Prime Numbers?

- Closed form for $ S(m) = \sum_{n=1}^\infty \frac{2^n \cdot n^m}{\binom{2n}n} $ for integer $m$?
- What is the next picture in this sequence?
- Permutations to satisfy a challenging restriction
- Point Group of a pattern
- What is this pattern found in the first occurrence of each $k \in \{0,1,2,3,4,5,6,7,8,9\}$ in the values of $f(n)=\sqrt{n}-\lfloor \sqrt{n} \rfloor$?
- Extract a Pattern of Iterated continued fractions from convergents
- How to solve this sequence $165,195,255,285,345,x$
- A random walk on a finite square with prime numbers
- Palindromic Numbers - Pattern “inside” Prime Numbers?
- How to solve the sequence: $87, 89, 95, 107, ?, 157$

Note that $1+3+4+9=17$ and $1+7+1+0=9$.

- moment generating function
- Special linear group as a submanifold of $M(n, \mathbb R)$
- Difference between logarithm of an expectation value and expectation value of a logarithm
- An easy example of a non-constructive proof without an obvious “fix”?
- Move the last two digits in front to multiply by $6$
- Explaining Newton Polygon in elementary way
- Another trigonometric proof…?
- Closed form of $\sum \frac{x^n}{n^n}$
- Integers that satisfy $a^3= b^2 + 4$
- Why do some people place the differential at the beginning of their integral?
- Prove that 1+1=2
- Example of non-isomorphic structures which are elementarily equivalent
- How can you prove that a function has no closed form integral?
- Explicit examples of infinitely many irreducible polynomials in k
- Is there a retraction of a non-orientable manifold to its boundary?