isogonal conjugates가 무슨뜻인지 아시는 분 설명 부탁 드립니다

[장나라♡]

올림피아드 문제 풀이 중에... 아래에 밑줄친 부분의 뜻이 뭔가요?

[Problem] : Let AE and BF be altitudes, and H the orthocentre, of acute triangle ABC. The reflection of AE across the interior angle bisector of A meets the reflection of BF across the interior angle bisector of B meet in a point O. The lines AE and AO meet the circumcircle of ABC again at M and N, respectively. Let P, R, S be the intersection of BC with HN, BC with OM, HR with OP, respectively. Show that AHSO is parallelogram.

[Solution] : Note that O and H are isogonal conjugates, where H is orthocentre of ABC and O is centre of circumcircle of ABC.
First we shall prove that AO || HR. AO = OM = R. It's easy to see that HE = EM. (<HBE = < EBM = 90 - <c)
So <AOM = < OMA = <RMH = < RHM => AO || HR.
AN = 2R, and <AMN = 90. <AEP = 90, and we conclude that EP || MN. From HE = EM we get that P is midpoint of line NH. O is midpoint of AN so OP || AH in triangle AHN.
AO || HR and OP || AH => AHSO is paralelogram.

[비는아픔]

http://en.wikipedia.org/wiki/Isogonal_conjugates

[newtonians]

여기 사이트로 가시면 바로 isogonal conjugate의 뜻을 알수 있습니다. http://mathworld.wolfram.com/IsogonalConjugate.html