y=(4x²-1)÷(x²-1)=4+[3/(x²-1)]=4+(3/2)*[1/(x-1)]-(3/2)*[1/(x+1)]；y'=-(3/2)/(x-1)²+(3/2)/(x+1)²；y"=(3/2)(1*2)/(x-1)³-(3/2)(1*2)/(x+1)³；……y'(n)=(-1)^n(3/2)*n!/(x-...