F2(X2 + Y2) = y12 + y22 + y32 − G2,

(21)

F(X + Yi) = Fy3 − Gx3 + i √ X3εψi.
√ (F2 − x32)

(22)

Suppose x3 − F is a repeated factor of X3, then y3 = G, and

X3 = (x3 − F)2 [ p′ − p(x3 + F)2 + 2 q′ − qG (x3 + F) − G2 ],
r r

(23)

and putting x3 − F = y,

( dy) 2= r2y2 [ 4 p′ − pF2 + 4 q′ − qFG − G2 + 2 ( 2 p′ − pF + q′ − qG ) y + p′ − py2 ],
dt r rr rr

(24)