Root test

[yzaguir]

I would appreciate any help witht his problem.
I am supposed to find abs(Ak)^(1/k)
Ak = (9/4)(x^k/(k+4)^4)
i was thinking (x^k)^(1/k)=x
but do i do anything to the bottom as well??
would it be more like x/((x+4)^(4/k))??
Thank you again.

 

[pka]

PLEASE post the actual series.
We cannot understand from your work.

 

[yzaguir]

Σ(k=1->infinity) 8/3*((-1)^k*x^k)/((k+4)^(5/7))