00:01
So in this problem, we're given this graph of the population of an industrial city from 1950 to the year 2000, where this verbal x on the horizontal represents the years since 1950.
00:17
So we can see the graph goes up, hits some maximum, comes back down.
00:22
So the first thing we're asked is where is the graph increasing? remember, increasing means we're getting larger as we go from left to right.
00:30
So that means from here to here we're increasing.
00:42
Well, it turns out this is at 25 on the, if you look at the graph given.
00:48
So we could say it was increasing from 1950, because that's where x is zero, and then 25 years later to 1975.
01:03
So then where is it decreasing? well, this is a decreasing curve.
01:08
It's falling, going from left to right...