Question

Can someone help me solve this?
∞
∑ 4(-1)^i
i=1

Answer 1

\[\sum_{i=1}^\infty{4(-1)^i}\]

Answer 2

Looks like a divergent sum

Answer 3

How do you prove that it's a divergent?

Answer 4

Alternating series test should do the trick, unless it's actually convergent and I'm missing something here.

Answer 5

or geometric series test. simpler