The fourth power of $\sqrt{1+\sqrt{1+\sqrt{1}}}$ is: ${\textbf{(A) }\sqrt{2}+\sqrt{3}\qquad\textbf{(B) }\frac{1}{2}(7+3\sqrt{5}})\qquad\textbf{(C) }1+2\sqrt{3}\qquad\textbf{(D) }3\qquad \textbf{(E) }3+2\sqrt{2}$

Square $ABCD$ has side length $30$. Point $P$ lies inside the square so that $AP = 12$ and $BP = 26$. The centroids of $\triangle{ABP}$, $\triangle{BCP}$, $\triangle{CDP}$, and $\triangle{DAP}$ are the vertices of a convex quadrilateral. What is the area of that quadrilateral? [asy] unitsize(120); pair B = (0, 0), A = (0, 1), D = (1, 1), C = (1, 0), P = (1/4, 2/3); draw(A--B--C--D--cycle); dot(P); defaultpen(fontsize(10pt)); draw(A--P--B); draw(C--P--D); label("$A$", A, W); label("$B$", B, W); label("$C$", C, E); label("$D$", D, E); label("$P$", P, N*1.5+E*0.5); dot(A); dot(B); dot(C); dot(D); [/asy] $\textbf{(A) }100\sqrt{2}\qquad\textbf{(B) }100\sqrt{3}\qquad\textbf{(C) }200\qquad\textbf{(D) }200\sqrt{2}\qquad\textbf{(E) }200\sqrt{3}$

The function $f(x)$ has the property that, for some real positive constant $C$, the expression \[\frac{f^{(n)}(x)}{n+x+C}\] is independent of $n$ for all nonnegative integers $n$, provided that $n+x+C\neq 0$. Given that $f'(0)=1$ and $\int_{0}^{1}f(x) \, dx = C+(e-2)$, determine the value of $C$. Note: $f^{(n)}(x)$ is the $n$-th derivative of $f(x)$, and $f^{(0)}(x)$ is defined to be $f(x)$.

Given any real number $N_0,$ if $N_{j+1}= \cos N_j ,$ prove that $\lim_{j\to \infty} N_j$ exists and is independent of $N_0.$

Some identically sized spheres are piled in $n$ layers in the shape of a square pyramid with one sphere in the top layer, 4 spheres in the second layer, 9 spheres in the third layer, and so forth so that the bottom layer has a square array of $n^2$ spheres. In each layer the centers of the spheres form a square grid so that each sphere is tangent to any sphere adjacent to it on the grid. Each sphere in an upper level is tangent to the four spheres directly below it. The diagram shows how the first three layers of spheres are stacked. A square pyramid is built around the pile of spheres so that the sides of the pyramid are tangent to the spheres on the outside of the pile. There is a positive integer $m$ such that as $n$ gets large, the ratio of the volume of the pyramid to the total volume inside all of the spheres approaches $\frac{\sqrt{m}}{\pi}$. Find $m$. [center][img]https://snag.gy/bIwyl6.jpg[/img][/center]

Does there exists a positive irrational number ${x},$ such that there are at most finite positive integers ${n},$ satisfy that for any integer $1\leq k\leq n,$ $\{kx\}\geq\frac 1{n+1}?$

Let $ P_1,P_2,\ldots,P_8$ be $ 8$ distinct points on a circle. Determine the number of possible configurations made by drawing a set of line segments connecting pairs of these $ 8$ points, such that: $ (1)$ each $ P_i$ is the endpoint of at most one segment and $ (2)$ no two segments intersect. (The configuration with no edges drawn is allowed. An example of a valid configuration is shown below.) [asy]unitsize(1cm); pair[] P = new pair[8]; align[] A = {E, NE, N, NW, W, SW, S, SE}; for (int i = 0; i < 8; ++i) { P[i] = dir(45*i); dot(P[i]); label("$P_"+((string)i)+"$", P[i], A[i],fontsize(8pt)); } draw(unitcircle); draw(P[0]--P[1]); draw(P[2]--P[4]); draw(P[5]--P[6]);[/asy]

Which is greater: $ (3^5)^{(5^3)}$ or $ (5^3)^{(3^5)}$?

$ \left(\frac {(x \plus{} 1)^2(x^2 \minus{} x \plus{} 1)^2}{(x^3 \plus{} 1)^2}\right)^2 \cdot \left(\frac {(x \minus{} 1)^2(x^2 \plus{} x \plus{} 1)^2}{(x^3 \minus{} 1)^2}\right)^2$ equals: $ \textbf{(A)}\ (x \plus{} 1)^4 \qquad\textbf{(B)}\ (x^3 \plus{} 1)^4 \qquad\textbf{(C)}\ 1 \qquad\textbf{(D)}\ [(x^3 \plus{} 1)(x^3 \minus{} 1)]^2$ $ \textbf{(E)}\ [(x^3 \minus{} 1)^2]^2$

Find all primes $p,q, r$ such that $\frac{p^{2q}+q^{2p}}{p^3-pq+q^3} = r$. Titu Andreescu, Mathematics Department, College of Texas, USA

Consider all segments dividing the area of a triangle $ABC$ in two equal parts. Find the length of the shortest segment among them, if the side lengths $a,$ $b,$ $c$ of triangle $ABC$ are given. How many of these shortest segments exist ?

Let $k > 1$ be a positive integer and $n \ge 2019$ be an odd positive integer. The non-zero rational numbers $x_1, x_2,..., x_n$ are not all equal, and satisfy the following chain of equalities: $$x_1 +\frac{k}{x_2}= x_2 +\frac{k}{x_3}= x_3 +\frac{k}{x_4}= ... = x_{n-1} +\frac{k}{x_n}= x_n +\frac{k}{x_1}.$$ What is the smallest possible value of $k$?

The sum $$\sum_{m=1}^{2023} \frac{2m}{m^4+m^2+1}$$ can be expressed as $\tfrac{a}{b}$ for relatively prime positive integers $a,b.$ Find the remainder when $a+b$ is divided by $1000.$

Contessa is taking a random lattice walk in the plane, starting at $(1,1)$. (In a random lattice walk, one moves up, down, left, or right $1$ unit with equal probability at each step.) If she lands on a point of the form $(6m,6n)$ for $m,n \in \mathbb{Z}$, she ascends to heaven, but if she lands on a point of the form $(6m+3,6n+3)$ for $m,n \in \mathbb{Z}$, she descends to hell. What is the probability she ascends to heaven?

Let $m$ and $n$ be positive integers for which $n\leq m\leq 2n$. Find the number of all complex solutions $(z_1,z_2,...,z_m)$ that satisfy $$z_1^7+z_2^7+...+z_m^7=n$$ Such that $z_k^3-2z_k^2+2z_k-1=0$ for all $k=1,2,...,m$.

Let $n\geq2$ be an integer. An $n$-tuple $(a_1,a_2,\dots,a_n)$ of not necessarily different positive integers is [i]expensive[/i] if there exists a positive integer $k$ such that $$(a_1+a_2)(a_2+a_3)\dots(a_{n-1}+a_n)(a_n+a_1)=2^{2k-1}.$$ a) Find all integers $n\geq2$ for which there exists an expensive $n$-tuple. b) Prove that for every odd positive integer $m$ there exists an integer $n\geq2$ such that $m$ belongs to an expensive $n$-tuple. [i]There are exactly $n$ factors in the product on the left hand side.[/i]

Trapezoid $ ABCD$, with $ \overline{AB}\parallel{}\overline{CD}$, is inscribed in circle $ \omega$ and point $ G$ lies inside triangle $ BCD$. Rays $ AG$ and $ BG$ meet $ \omega$ again at points $ P$ and $ Q$, respectively. Let the line through $ G$ parallel to $ \overline{AB}$ intersects $ \overline{BD}$ and $ \overline{BC}$ at points $ R$ and $ S$, respectively. Prove that quadrilateral $ PQRS$ is cyclic if and only if $ \overline{BG}$ bisects $ \angle CBD$.

Given a finite sequence of real numbers $a_1,a_2,\dots ,a_n$ ($\ast$), we call a segment $a_k,\dots ,a_{k+l-1}$ of the sequence ($\ast$) a “[i]long[/i]”(Chinese dragon) and $a_k$ “[i]head[/i]” of the “[i]long[/i]” if the arithmetic mean of $a_k,\dots ,a_{k+l-1}$ is greater than $1988$. (especially if a single item $a_m>1988$, we still regard $a_m$ as a “[i]long[/i]”). Suppose that there is at least one “[i]long[/i]” among the sequence ($\ast$), show that the arithmetic mean of all those items of sequence ($\ast$) that could be “[i]head[/i]” of a certain “[i]long[/i]” individually is greater than $1988$.

Circle touches parallelogram‘s $ABCD$ borders $AB, BC$ and $CD$ respectively at points $K, L$ and $M$. Perpendicular is drawn from vertex $C$ to $AB$ . Prove, that the line $KL$ divides this perpendicular into two equal parts (with the same length).

Let $ABC$ be a scalene triangle with $I$ be its incenter. The incircle touches $BC$, $CA$, $AB$ at $D$, $E$, $F$, respectively. $Y$, $Z$ are the midpoints of $DF$, $DE$ respectively, and $S$, $V$ are the intersections of lines $YZ$ and $BC$, $AD$, respectively. $T$ is the second intersection of $\odot(ABC)$ and $AS$. $K$ is the foot from $I$ to $AT$. Prove that $KV$ is parallel to $DT$. [i]Proposed by ltf0501[/i]

Danielle divides a $30 \times30$ board into $100$ regions that are $3 \times 3$ squares squares each and then paint some squares black and the rest white. Then to each region assigns it the color that has the most squares painted with that color. a) If there are more black regions than white, what is the minimum number $N$ of cells that Danielle can paint black? b) In how many ways can Danielle paint the board if there are more black regions than white and she uses the minimum number $N$ of black squares?

We are given an acute-angled triangle $ABC$ with $AB < AC < BC$. Points $K$ and $L$ are chosen on segments $AC$ and $BC$, respectively, so that $AB = CK = CL$. Perpendicular bisectors of segments $AK$ and $BL$ intersect the line $AB$ at points $P$ and $Q$, respectively. Segments $KP$ and $LQ$ intersect at point $M$. Prove that $AK + KM = BL + LM$. Poland

Let $a,b,c$ be positive real numbers such that $abc=1$. Prove that $$\sqrt{\frac{a^3}{1+bc}}+\sqrt{\frac{b^3}{1+ac}}+\sqrt{\frac{c^3}{1+ab}}\geq 2$$ Are there any triples $(a,b,c)$, for which the equality holds? [i]Proposed by Konstantinos Metaxas.[/i]

For all odd natural numbers $ n, $ prove that $$ \left|\sum_{j=0}^{n-1} (a+ib)^j\right|\in\mathbb{Q} , $$ where $ a,b\in\mathbb{Q} $ are two numbers such that $ 1=a^2+b^2. $

On the graph of a polynomial with integer coefficients, two points are chosen with integer coordinates. Prove that if the distance between them is an integer, then the segment that connects them is parallel to the horizontal axis.