00:01
Once again, i welcome to new problem.
00:05
When you think about sets, so when you think about set, a set is a collection.
00:13
A set is a collection of elements.
00:16
So this is when you're thinking about sets and what tends to happen.
00:21
If i have a set a with a bunch of elements, say one, two, three, four, and five.
00:30
And then i also have another set b with a bunch of elements, one, two, three.
00:37
So b is going to be a subset of a, for example, b can be a subset of a.
00:45
And then also, if you think about two sets in b, a union b would be the union of two sets, and that involves the elements, the elements in both a and b.
01:08
So the elements in both a, not nb, but orb.
01:13
So that's pretty much all the elements.
01:15
And then if you have a intersection b, these are common elements, common elements in both a and b.
01:28
So the sets in b and then we could also have a minus b.
01:35
So these are elements that exist in a but not in b.
01:50
And then also a complement is all the elements, all the elements, all the elements not in so we have a new problem and in the problem we have a, these are the students, these are the students living within one mile of the school.
02:26
And then b is students walking to classes, students working to classes.
02:37
So in part a, we're saying what's a intersection b? so we want to describe all of these...