- #1
sony
- 104
- 0
Ok so I have found a formula for d^n/dx^n 1/x^2
= (-1)^n * (1+n)! * x^-(n+2)
So I have to do d/dx [(-1)^n * (1+n)! * x^-(n+2)] and see what I end up with. But how do I do that.
My book gives an example: (from d/dx (1+x)^-1)
d/dx [(-1)^k * k!(1+x)^(-k-1)] = (-1)^k * k!(-k-1)(1+x)^(-k-2)=...
What on Earth is going on?! My book just drops explaning _how_ . Where does (-k-1) come from? I'm stuck...
Thanks
= (-1)^n * (1+n)! * x^-(n+2)
So I have to do d/dx [(-1)^n * (1+n)! * x^-(n+2)] and see what I end up with. But how do I do that.
My book gives an example: (from d/dx (1+x)^-1)
d/dx [(-1)^k * k!(1+x)^(-k-1)] = (-1)^k * k!(-k-1)(1+x)^(-k-2)=...
What on Earth is going on?! My book just drops explaning _how_ . Where does (-k-1) come from? I'm stuck...
Thanks