hey can someone please see if I did this right,

x--> infinity, (4x+9) / (7x^2 +4x - 9)

take the derivative = 4 / 14x + 4

so would it be 0? if not i'm not sure what to do next.

and

the integral from 0 to infinity of 1 / (x(x^2)+5)

so i did 1 / x^3 + 5x then i can't take the derivative again b/c the numerator is 1. now i don't know what to do.

any help is much appreciated.