00:01
We want to find the limit of this sequence.
00:03
So here's the thing.
00:04
I'm going to define a as that limit.
00:12
Okay.
00:13
And i'm going to take the limit of both sides of this equation.
00:33
All right.
00:37
And so the left -hand side is just a.
00:42
And the right -hand side is this.
00:49
All right.
00:49
And then i'll square it.
00:57
All right.
00:57
And then i can subtract a -squared.
01:12
Both sides i get zero, which looks like it tells us a is minus three halves.
01:48
So here's the thing.
01:51
If we understand the square root to be the positive square root, this is never going to happen.
02:05
Because what's going to happen is every time that we take that square root, we're going to get a positive number.
02:11
We plug it back in there, we're going to get another positive number, which is actually bigger.
02:16
The only way to get to this is if we allow ourselves to take the negative square root.
02:27
But by definition, the square root is supposed to be positive.
02:35
Therefore, it diverges.
02:55
For the next one, so we're told that, all right, and we want to figure out this.
03:29
All right.
03:30
Well, i'm going to make life a little easier and rewrite this because x makes it confusing.
03:38
Because this x and that x are clearly not the same.
03:44
So i'm going to define this to be y like that.
03:59
Okay.
04:00
And then i'm going to define x equals 1 minus y.
04:08
All right...