I've been trying to find the general formula for the following problem but I can't seem to find anything in common.

Find a general formula for f^k (x) (the kth derivative of f) if f = 1 / (x^2-1)

f=1/[(x^2)-(1)]

So I found f ' and I got:

2x/ (x^2-1)^2

f '' :

2 (3x^2-1) / (x^2-1)^3

so I'm having difficulty with finding the general formula.

I know the denominator changes you'll have (x^2-1) always, but since the power is always increasing so...you'll have something like...

(x^2-1) ^k+1.

## Error