Question

use the integral test to determine whether the series is convergent or divergent: n^2/e^n

Answer 1

from n = 3 to infinity

Answer 2

so plug and chug. Using
∫[3,∞] x^2/e^x dx
do this using integration by parts (twice), since it is just
∫[3,∞] x^2 e^(-x) dx = (x^2+2x+2) e^(-x)
so, does that integral converge or diverge?