IMO 2015 zadatak 3
Kvaliteta:
Avg: 4,0Težina:
Avg: 7,5 Neka je
šiljastokutni trokut u kojem je
. Neka je
njegova opisana kružnica,
njegov ortocentar, te
nožište visine iz
. Neka je
polovište dužine
. Neka je
točka na kružnici
takva da je
i neka je
točka na kružnici
takva da je
. Pretpostavlja se da su točke
,
,
,
i
u parovima različite i da leže na kružnici
tim redom.
Dokaži da su opisane kružnice trokuta
i
dodiruju.
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Dokaži da su opisane kružnice trokuta
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Izvor: Međunarodna matematička olimpijada 2015, prvi dan