458] 
OX THE AXHAKMOXIC-RATIO SEXTIC. 
315 
when X has any one of the values t , -r, -?=, -r, tv> t > we see that u assumes 
J B A G A G B 
only the values A, B, G, and u is thus determined by the equation 
u 3 -12Iu - 16 V(A) = 0. 
Eliminating u, we obtain 
or, what is the same thing, 
4A(x + l + l)'-27/=(x+i + 2) = 0 , 
that is 
4A (X 2 + X + l) 3 - 27/ 3 X 2 (X + l) 2 = 0, 
the required equation. 
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40—2