00:01
In this problem, we have the set p representing the set of all integers greater than one, and for all i greater than or equal to 2, xi is defined as the set ik, says that k belongs to p.
00:18
And we need to describe p minus the union of xi, where i ranges from 2 to infinity.
00:27
So first of all, have a look at each set xi.
00:31
So for i greater than or equal to 2, xi is equal to ik where k belongs to p.
00:37
And k is an integer greater than 1.
00:39
So what do we end up with? this set will actually represent the multiples of the numbers i.
00:49
For example, if i is 2, if we have i to be 2, then x2 will be ik where k is an integer greater than 1.
00:57
So case starts from 2.
00:59
So we have 2 times 2 that's 4, 2 times 3 that's 6, and we have 2 times 4, that's 8, and so on.
01:06
So we end up with all of the positive multiples of 2 except for the number 2 itself...