Question

Prove the lim n->inf of k^2 * (-1)^k

Answer 1

there is no n in your expression...so limit would just be k^2 * (-1)^k

Answer 2

my bad. yes as k goes to infinity

Answer 3

the limit does not exist

Answer 4

i know it diverges

Answer 5

cause its going to oscillate to - and + infinity right?

Answer 6

yes

Answer 7

but do you know how to show/prove that?

Answer 8

can you prove that \[\lim_{k\to\infty}k^2=\infty\]

Answer 9

yea through the ratio test

Answer 10

and the limit test.

Answer 11

but you cant prove the other one through the ratio test because its not a positive series.

Answer 12

ratio test is for series