Wikipedia:Reference desk/Archives/Mathematics/December 2021

= December 4 = Reference_desk/Archives/Mathematics/2021 December 4


 * 1) What's the way to know what country is located 180 degrees from some specific city of another country?
 * 2) Geometric shape for four (or more) cylinders around a central cylinder

= December 5 = Reference_desk/Archives/Mathematics/2021 December 5


 * 1) Improving secrecy
 * 2) Density of logical valid statements

= December 6 = Reference_desk/Archives/Mathematics/2021 December 6


 * 1) Pattern in last 2 digits of polygonal numbers

= December 7 = Reference_desk/Archives/Mathematics/2021 December 7


 * 1) Lagrangian vs Eulerian specifications of a field

= December 9 = Reference_desk/Archives/Mathematics/2021 December 9


 * 1) Huge cardinal

= December 12 = Reference_desk/Archives/Mathematics/2021 December 12


 * 1) Brackets in direct products of groups
 * 2) The pons asinorum of logic
 * 3) Chance to win a chess game

= December 13 = Reference_desk/Archives/Mathematics/2021 December 13


 * 1) Ex nihilo, 1

= December 15 = Reference_desk/Archives/Mathematics/2021 December 15


 * 1) Maximum break in snooker

= December 17 = Reference_desk/Archives/Mathematics/2021 December 17


 * 1) line integral and length

= December 20 = Reference_desk/Archives/Mathematics/2021 December 20


 * 1) Approximation of the product of all primes not larger than a given prime.

= December 22 = Reference_desk/Archives/Mathematics/2021 December 22


 * 1) Rotation of a cube on its vertex
 * 2) The very word "primorial"
 * 3) Question about the Hadwiger–Nelson problem

= December 25 = Reference_desk/Archives/Mathematics/2021 December 25


 * 1) Rotating the other Platonic solids

= December 27 = Reference_desk/Archives/Mathematics/2021 December 27


 * 1) On two (supposedly solved) problems

= December 30 = Reference_desk/Archives/Mathematics/2021 December 30


 * 1) Real unit disc
 * 2) certain restricted permutations

= December 31 = Reference_desk/Archives/Mathematics/2021 December 31


 * 1) Number theory
 * 2) Sum of reciprocals