Τρίτη 22 Οκτωβρίου 2019

HYACINTHOS 23820

Antreas P. Hatzipolakis

 [APH]:


Let ABC be a triangle, P a point and A'B'C' the pedal triangle of P.

Denote:

Ba, Ca = the orthogonal projections of B', C' on AB, AC, resp.

Which is the locus of P such that the Euler line La of ABaCa is perpendicular

to BC?

N lies on the locus.

We have three loci corresponding to A,B,C

 

Which points, other than N, are their intersections?

 

[César Lozada]:

 

For A,B,C the required loci are the correspondent cevian of N, together with the line at infinity.

 

For P=N the Euler lines La, Lb, Lc concur at:

 

Z= (cos(2*A)-2)*cos(B-C)+cos(A) :: (trilinears)

= X(4)+3*X(51)

= midpoint of X(i),X(j) for these {i,j}: {4,389}, {5,5446}, {52,5907}, {143,546}, {1112,7687}, {5480,9969}                  

= reflection of X(i) in X(j) for these (i,j): (5447,3628), (9729,5462)

= On lines:

(3,5943), (4,51), (5,141), (6,1598), (20,5640), (25,578), (30,5462), (49,7545),    

 (52,381), (54,1495), (64,3531), (68,3818), (140,6688), (143,546), (155,576),       

 (181,3073), (182,7387), (373,631), (382,9730), (403,3574), (428,6146), (517,5795),  

 (550,5892), (568,3843), (569,7517), (575,7530), (970,3560), (973,1112), (1092,1995),

(1154,3850), (1173,1199), (1181,5198), (1597,3357), (1656,3819), (1843,3089),      

 (1864,1871), (1872,2262), (2818,7686), (2979,5056), (3060,3091), (3072,3271),       

 (3090,3917), (3098,7393), (3627,5946), (3628,5447), (3832,5889), (3845,6102),      

 (3851,5891), (3858,5876), (3861,5663), (5067,5650), (5071,7999), (5752,6913),      

 (6403,6622), (6530,6750), (6995,9833), (7486,7998), (7529,9306)

= {X(i),X(j)}-Harmonic conjugate of X(k) for these (i,j,k):

(4,51,389), (4,1093,8887), (4,3567,185), (4,9781,51), (6,1598,6759), (51,185,3567),

 (52,381,5907), (185,3567,389), (1597,9786,3357), (1598,3527,6), (3060,3091,5562),  

 (3851,6243,5891), (5198,9777,1181)

= [ -1.328685665701012, -1.74991120893009, 5.465381010721065 ]

 

César Lozada
 

 

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