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IMO 1969 - Longlist Problems Question 2

IMO Shortlist · IMO 1969 - Longlist Problems

Question 2

(BEL 2)
(a) Find the equations of regular hyperbolas passing through the points $A(\alpha,0)$, $B(\beta,0)$, and $C(0,\gamma)$.
(b) Prove that all such hyperbolas pass through the orthocenter $H$ of the triangle $ABC$.
(c) Find the locus of the centers of these hyperbolas.
(d) Check whether this locus coincides with the nine-point circle of the triangle $ABC$.