776]
ON THE JACOBIAN SEXTIC EQUATION.
399
I consider the general quintic (a, 5, c, d, e, f^x, 1) 5 = 0; taking the roots to be
Xi, x 2 , x 3 , x 4 , x 5 , and writing
04 = 12345 - 24135,
0 2 = 13425 - 32145,
0 3 = 14235 — 43125,
0 4 = 21435 - 13245,
0 5 = 31245 - 14325,
0 6 = 41325 -12435,
where 12345 is used to denote the function
= (xjx 2 + x& 3 + x 3 x 4 + XiX 5 + x 5 Xj) V(20),
(this numerical factor \/(20) being inserted for greater convenience), then the equation
whose roots are 0 1} 0 2 , 0 3 , 0 4 , 0 5 , 0 8 , which equation may be regarded as the resolvent
sextic of the given quintic equation, is
a 6 x
— 5a 4 x
5a 2 x
a 2
+ 5
1
' 0 '
ae
2 a?df
+ 1
+ 1 ct 3 cf 3
— ibd
+ 3 a 2 e 2
— 2a?def
+ 3c 2
&c.
+ &c.
1) 6 = 0,
□ =a 4 / 4 + &c., the discriminant of the quintic: see p. 274* of my paper “On a new
auxiliary equation in the theory of equations of the fifth order,” Phil. Trans, t. CLI.
(1861), pp. 263—276, [268].
I now write 5 = 0, d = 0, but, to avoid confusion again, write roman instead of
italic letters, viz. I consider the resolvent sextic of the quintic equation
(a, 0, c, 0, e, l) 5 .
Many of the terms thus vanish, and the equation assumes the form
a 6 x
— 5a 4
5a 2
| 1
1 □
+ 5
' 1 '
0
ae + 1
a 2 e 2 + 3
+ 1
a 3 cf 2 + 1'
c 2 + 3
ac 2 e — 2
a 3 e 3 + 1
c 4 + 15
a 2 c 2 e 2 - 11
ac 4 e +35
c 6 - 25
and then if, as before,
a = 1, c = 2d, e = — 95/+ 36c£ 2 , f 2 = 216/i,
or say
a = 1, c = 2 \/8, e = — 9/3 + 36S, f 2 =216/i,
* [This Collection, vol. iv., p. 321.]