414]
ON POLYZOMAL CURVES.
513
where we see that the two equations are equivalent to each other and to the
equation
l x m, n x p x .
- + vr + — +4 = o.
a x b x Cj dj
It thus appears that the quantities l x , m x , n x , p x , must satisfy this last equation. It
is to be observed that the first and second equations being, as we have seen, equivalent
to a single equation, either of the quantities m x , n x , may be assumed at pleasure, but
the other is then determined; the third and fourth equations then give l x , p x ; and the
101. Now writing
ff'li ——9 (c'm + b'm x ) + h (b'n + cn x ),
f/Pi = ~c (gm- h'm x ) + b (h'n-g'n x ),
and
ff'p = c (c'm + b'nii) + b (b'n + cn y ),
ffl = 9 (g'm ~ h'rth) + h (h'n - g'n^,
we find
pp {lp x — lp)= — (bg + ch) [(c'm + b'm x ) (h'n — g'n x ) + (g’m — h'm x ) (b'n + c'wj)],
= (bg + ch) (b'g' + c'h' ) (mgix — mn),
= (Miff (m x n x — mn),
that is
ff (hpi — Ip) = (Mi (m x n x — mn)
viz., this equation is satisfied identically by the values of l x , m x , n x , p x determined as
above.
102. Hence if m x n x — mn, we have also l x p x = Ip, and we can determine m x , n x> so
that m x n x shall = mn, viz., in the first or second of the four equations (these two being
equivalent to each other, as already mentioned), writing m x = 6n, and therefore n x = ^ m,
we have
—ffl + gg'm + lilt n — glind — g'hm ^ = 0,
cc'm + bb'n — ff p + cb'nO + be'm - = 0,
which are, in fact, the same quadric equation in 6, viz., we have
—ffl + gg'm + hh'n _ gh' _ g'h
cc'm + bb'n — ffp cb' be'
The final result is that there are two sets of values of l x , nh, n x , p x , each satisfying
the identity
- № + + n& - pQ + l$L x — — W!®! + p x 9ö x = 0,
C. VI.
65