olymmath

OLYMPIC-REVENGE 2023

Olympic Revenge 2023.

Other problems

Problem 1

Find all f:R→Rf:\mathbb{R}\rightarrow \mathbb{R} continuous functions such that lim⁡x→∞f(x)=∞\lim_{x\rightarrow \infty} f(x) =\infty and ∀x,y∈R,∣x−y∣>φ,∃n<φ2023,n∈N\forall x,y\in \mathbb{R}, |x-y|>\varphi, \exists n<\varphi^{2023}, n\in \mathbb{N} such that fn(x)+fn(y)=x+yf^n(x)+f^n(y)=x+y

Problem 2

Find all triples ( aa , bb , nn ) of positive integers such that a3=b2+2na^3=b^2+2^n

Problem 3

Define a big circle\emph{big circle} in a sphere as a circle that has two diametrically oposite points of the sphere in it. Suppose (AB)(AB) as the big circle that passes through AA and BB . Also, let a Spheric Triangle\emph{Spheric Triangle} be 33 connected by big circles. The angle between two circles that intersect is defined by the angle between the two tangent lines from the intersection point through the two circles in their respective planes. Define also ∠XYZ\angle XYZ the angle between (XY)(XY) and (YZ)(YZ) . Two circles are tangent if the angle between them is 0. All the points in the following problem are in a sphere S. Let ΔABC\Delta ABC be a spheric triangle with all its angles <90∘<90^{\circ} such that there is a circle ω\omega tangent to (BC)(BC) , (CA)(CA) , (AB)(AB) in D,E,FD,E,F . Show that there is P∈SP\in S with ∠PAB=∠DAC\angle PAB=\angle DAC , ∠PCA=∠FCB\angle PCA=\angle FCB , ∠PBA=∠EBC\angle PBA=\angle EBC .

Problem 4

Let S={(x,y,z)∈Z3}S=\{(x,y,z)\in \mathbb{Z}^3\} the set of points with integer coordinates in the space. Gugu has infinitely many solid spheres. All with radii ≥(π2)3\ge (\frac{\pi}2)^3 . Is it possible for Gugu to cover all points of SS with his spheres?