00:01
Okay, we have a given series, and the first thing we're going to do is find the sum of the series.
00:09
So in order to do that, we are going to have to use partial fractions.
00:13
So i'm going to do an a over n plus a b over n plus 3.
00:19
Now, when writing out your partial sums, you have your numerator equals, and then considering you're doing the common denominator to get back to the original.
00:27
So my a is going to have to be multiplied by that n plus three, as would bottom would have to be.
00:35
B will get multiplied by n.
00:37
And then i can consider a nice place.
00:41
So at n equals zero, b will go away, and i can solve for a.
00:45
That will give me an a value of two.
00:48
Another good place would be n equals negative three.
00:53
Here, a will zero out, and i'll have six.
00:57
Equals negative 3b making b a negative 2.
01:03
So now i can rewrite my partial sums with my a and b value...