400] 
GIVEN PENCIL OF SIX LINES. 
115 
and when the symmetric functions have been expressed in terms of the coefficients, 
the result is to be expressed as a function of □, V, ©, R by means of the values 
c-Q = a 2 b 2 + 4 ak 3 + 4 bh 3 — 6 adhk — 3 h 2 k 2 , 
V = -1\ 
c© — — l (ah — hk), 
cR = — 8 l 3 ab. 
Thus, for instance, the first term of the result is 
= c 2 R 2 .8 Pa*. 512 l s xfx£x£, 
which is 
= c 2 R 2 .4096£ 12 a 2 6 2 , 
= c 2 R 2 . -64c 2 E 2 V 3 , 
= -64 c 4 E 4 V 3 , 
which is a term in the before-mentioned expression for Q 10 . 
15—2