where ak= (7^n)/(3n^6+4^n)

I tried the alternating series test but I get stuck on determining whether or not it is decreasing (using derivative)

Also this other problem test for absolute convergence, conditionally convergent or divergent

infinity

E (-1)^n (4n^8+4)/(8n^9+2)

n=1

how would i test this for absolute convergence? I tried ratio test and it just becomes a bigger mess