00:01
We're being asked to find the sum of this particular series.
00:04
Well, let's pick out the information that we know.
00:06
When we know the first term is equal to 1, so we know the a sub 1 is 1.
00:10
We know the last term is 59, so a sub n is equal to 59.
00:15
And we know our common difference is going to be 2, because to get from one term to the next, we're simply adding 2.
00:22
So what we need to do is we need to find n.
00:25
To do this, we're going to use our general form to find the nth term in the arithmetic sequence.
00:31
Which is a sub m equals a sub 1 plus the quantity of m minus 1 times d.
00:37
So let's substitute these values in that we know.
00:40
Well, we have 59 equals 1 plus the quantity of m minus 1 times 2.
00:47
So to solve, i'm going to subtract 1 from both sides...