MathDB

1

Part of 2013 Germany Team Selection Test

Problems(2)

Injectivity on Ratinoals

Source: Germany TST 2013 P1

4/14/2020
nn is an odd positive integer and x,yx,y are two rational numbers satisfying xn+2y=yn+2x.x^n+2y=y^n+2x.Prove that x=yx=y.
number theory
A TST Problem That Makes You Think Is This Really a TST Problem

Source: Germany TST 2013 P4

4/14/2020
Two concentric circles ω,Ω\omega, \Omega with radii 8,138,13 are given. ABAB is a diameter of Ω\Omega and the tangent from BB to ω\omega touches ω\omega at DD. What is the length of ADAD.
geometry