596
PROBLEMS AND SOLUTIONS.
[485
Taking x = 0, y = 0, z = 0 for the equations of the sides of the triangle ABG, the
equations of the three conics may be taken to be U = 0, V = 0, W = 0, where the
functions U, V, W are such that identically U + V + W = 0; and then observing that
C
the conics pass through the points (y = 0, z = 0), (z = 0, x = 0), (x= 0, y — 0), respectively,
we see that the equations may be taken to be
( 0, - b, c, f lt g x , Jh\x, y, z) 2 = 0,
(a, 0, - c, / a , g 2 , K\x, y, zf = 0,
(-a, b, 0, /, g 3 , h 3 \x, y, z) 2 = 0,
where
fi +f2 +/3 = 0, g x + g. 2 4- g 3 =0, h x + h. 2 + h 3 = 0.
The coordinates of the points a, /3, y, a, ¡3y are at once found to be
a,
(
0 ,
0,
- 2^1) ;
a', ( b ,
2/q,
0)
Â
(-
2L,
a,
0 );
ß\ ( 0,
c ,
2/ 2 )
7»
(
0,
-2/3,
b );
7> (2^3>
0,
a )
and hence the equations of /3y', ya, a/3' are
¡3y ; ax + 2h 2 y — 2g 3 z = 0,
ya' ; — 2hjx + by + 2f 3 z = 0,
a/3'; 2g x x - 2f 2 y + cz = 0.
Hence for the point A', which is the intersection of ya', a/3', coordinates are
be + 4/, / 3 , 4/3 g x + 2ch x , U x f, -2bg 1 ;
and A' will be on the first conic if only
(0, - b, c, /, g x , hffbc + 4/ 2 / 3 , 4f 3 g x + 2ch x , 4h x f - 2bg x f = 0,
viz. this equation is
- b ( 16f 3 2 g x 2 + 1 QfsgAc + 4h x 2 c 2 )
+ 0 ( I6V/2 2 -1 Qf^gAb + 4<7 1 2 6 2 )
+ 2/i( IQgAfifs- tyifsb +8h 1 2 f 2 c-4 ! g 1 h 1 bc)
+ 29i (+ 16/q/ 2 2 / 3 - 8g x f 2 f 3 b + 4 hf'.bc - 2g 1 b 2 c )
+ 2 Jh (+ 16gf,f. 2 + 8 h x f 2 f 3 c + *g x f 3 bc + 2 h x bc 2 ) = 0,