[710
710]
ON A DIFFERENTIAL EQUATION.
19
irithm of a
its of which
the integral
2, where fl
r , D are of
,1 is
are rational,
uation
I had previously obtained the solution
/1 — \Za?y
Vl+^V ’
and I wish to show that this is, in fact, the particular integral belonging to the value
0=1 of the constant of integration : for this purpose I proceed to rationalise the general
integral as regards
Writing for a moment
P = 0+ 1)0 2 - 34*+1),
Q = (z 2 + 14;z + l)Vp + 14^+ 1,
JR, = MOz (z — l) 2 ,
where
M — C + 1) ( x ‘ ~ 34a? 4-1) 4- (a? 2 4- 14# + 1) Va? 2 4- 14a? + 1
Va? (a? — I) 2
the integral is P + Q + JR = O', or rationalising, it is
(P 2 - QJ - 2P 2 (P 2 + Q 2 ) + P 4 = 0;
we have
P 3 = ( 1, -66, 1023, 2180, 1023, - 66, 1\z, l) 6 ,
Q 2 = (l, 42, 591, 2828, 591, 42, 1 \z, l) 6 ,
onr] thpiipp
P 2 -Q 2 = (0, -108, 432, -648, 432, -108, 0\z, l) 6 ,
= - 108^(^ — l) 4 ;
P 2 4- Q 2 = 2 (1, -12, 807, 2504, 807, - 12, 1\z, l) 6 .
Writing the equation in the form
i(P’ + <?) - 1 y+=0,
it thus becomes
(1, -12, 807, 2504, 807, -12, 1\z, l) s -z(z-l) 4 jilP + = 0,
where M has its above-mentioned value; and if we now assume 0=1, then
(a? + 1) (a? 2 — 34a? 4-1) 4- (a? 2 + 14a? + l)Va? 2 + 14a? + 1
= Vx (a? — l) 2 ’
108 (a? 4-1) (a? 2 — 34a? 4-1) — (a? 2 4- 14a? 4-1) Va? 2 4-14« 4- T
M Va?(a?—I) 2
and thence
.ZIP 2 4-
(108) 2
if 2 ’
M -
108V
M)
+ 216, =4 (« + iry-34r + iy + 216|
00 \X JL )
a? (a? — 1)'
.(1, -12, 807, 2504, 807, -12, l\x, l) 6 :
3—2