求y=（4x∧2-1）÷（x∧2-1）的n阶导数

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-1)^(n+1)-(-1)^n(3/2)*n!/(x+1)^(n+1)
=(3/2)*{n!/[(-x-1)^(n+1)]-n!/[(1-x)^(n+1)]}；