00:01
Okay, so let's get started with part a of our exercise.
00:04
Well, here we have the series associated to the sequence 1 over n factorial.
00:12
Now, what is limit as n goes to infinity of a n plus 1 over a n? well, easy.
00:22
This guy here is n factorial over n plus 1 factorial, which is 1 over, oh, here, okay.
00:33
Let me write, let me just write a n plus 1 over a n.
00:38
Okay.
00:38
Ok, here we have n factorial over n plus 1 factorial, which is 1 over n plus 1.
00:46
And this shows that limit as n goes to infinity of a n plus 1 over a n is the limit of this one, which is 0.
00:57
Perfect.
00:57
So the ratio test shows that the series associated to this sequence is convergent.
01:04
Now, b.
01:07
Well, here we have the series associated to an equal to x to the n over n factorial...