00:01
So the way i'm seeing this, i'm going to do letter a, is that you have a circle.
00:07
Well, x squared plus y squared is a circle centered at the origin.
00:11
I'm going to go ahead and write 5 squared, because in the equation of a circle, this is r squared, and 5 squared is 25, and that'll help you see that r equals 5.
00:23
So 1, 2, 3, 4, 5.
00:26
1, 2, 3, 4, 5.
00:28
1, 2, 3, 4, 5.
00:30
And 1, 2, 3, 4, 5.
00:33
And our graph looks something like this.
00:41
So then what we're trying to do is maximize an area.
00:44
So i don't know if they want you to draw a picture in here.
00:50
It would look something like this.
00:53
And that's not a perfect picture.
00:56
But the area, if we have ordered pairs here of x, y, what you have to realize, though, is we're trying to maximize.
01:04
And x starts at the origin, right? x up y.
01:07
So the area is actually 2x times 2y.
01:12
And at that point, i would actually rewrite it as 2 times 2 is 4.
01:20
I'm getting ahead of myself.
01:22
You have this x here.
01:23
But then you want to actually solve for y out of this function.
01:28
So y would equal 25.
01:30
You subtract x squared to the right side, and then you'd square root that.
01:34
But the issue is, let's just leave it like that.
01:38
Actually, let's rewrite as 25 minus x squared to the 1 half power.
01:44
So now i can take this derivative...