f(x)=x²-3x+1/(x-1)+3
f'(x)=2x-3-1/(x-1)²
令f'(x)=0得：
2x-3-1/(x-1)²=0
(2x-3)(x-1)²=1
2x³-7x²+8x-4=0
(x-2)(2x²-3x+2)=0
则x=2
∵1