00:01
What makes the limit as n goes to infinity of a .n a little bit awkward is this cosine of n pi.
00:09
Because limit as n goes to infinity of cosine of n pi, that limit does not exist.
00:15
So cosine of n pi is the thing that's causing us some trouble here.
00:20
But we can still work with it.
00:21
Cosine of n pi is bounded.
00:23
So it's going to be somewhere between minus 1 and 1.
00:28
So regardless of what n is, cosine of n pi is going to be between.
00:33
Minus 1 and 1.
00:37
And now if we multiply by 2 to the minus n, which is the same thing as dividing by 2 to the end, then we still have these bounds here because 2 to the n is just going to be some positive number.
00:52
So if we're multiplying or dividing by a positive number, then we don't have to worry about switching these inequality signs...