X^2-X+1分之X+1dx
=1/2*S(1/(X^2-X+1))d(X^2-X+1)
+3/2*S(1/[(x-1/2)^2+3/4]d(x-1/2)
=1/2*ln(X^2-X+1)+
(根号3)*arctan[2(x-1/2)/(根号3))]+C