Judging by your recent post on meta, I guess that you might be interesting in my effort to collect somewhere unresolved bounties. For details see meta and this chat room. Feel free to ping me here or in chat after you saw this message. (Since it is unrelated to the question, I prefer removing it after it served its purpose.) — Martin Sleziak 7 hours ago
As preparation for math competitions such as this one, I'm looking for useful lower-level mathematical formulas that are useful for a variety of problems.
Some formulas that I've found very useful so far are
Vieta's formulas
$r_1+r_2=\frac{-b}a$, $r_1r_2=\frac ca$
Euclidian Algorit...
