00:01
In part a, we want to write this sequence here in sigma notation.
00:14
So take note that this is actually an ap arithmetic progression because the increase is by a constant number and that is one.
00:23
So i'm going to let the first term be a.
00:31
And we also know that the common difference between each term is a plus one.
00:39
Because this is constant.
00:43
It is an ap.
00:45
So this is called the common difference or d and that will be 1.
00:50
So we want to find the nth term denoted by un and that would be by the formula a plus n minus 1d.
01:02
So this is for sequences that are ap.
01:09
Now, n is the number of terms or the nth term in this case.
01:18
So a is 3 and d is 1.
01:22
And so we have 3 plus n minus 1 and that will be n plus 2.
01:28
So in this case, our set notation here, sigma notation would be n is running from 1 to there is this upper limit that we need to take note.
01:41
And that is how many number of terms are here...