00:01
And hello, we are looking at chapter 12, section 5, problem number 5.
00:07
So we want to find a taylor series expansion for our function f of x equals 5 over 2 minus x, and also find the interval of convergence.
00:19
So what i want to start with is the elementary tailor series for 1 over 1 minus x, since that's going to match up pretty well with what we're looking for.
00:30
So i'll write that right here.
00:33
So this is our given elementary series that we know 1 over 1 minus x.
00:38
We know is 1 plus x plus x squared plus and then it keeps going.
00:45
We get to our nth term, x to the n, and still keep going.
00:52
And this would be true for negative 1 is less than x is less than 1.
00:59
So that's its interval of convergence.
01:03
So what we need to do is alter that to make it match 5 over 2 minus x.
01:08
So we're going to do this in two steps.
01:12
So my first step i'm going to replace x with x over 2.
01:29
So that would look like 1 over 1 minus x over 2.
01:38
And so i change every term or every x in my expansion.
01:43
I change to x over 2.
01:45
So the 1 is going to stay 1, but x is going to become x over 2.
01:51
X squared becomes x over 2 quantity squared.
01:56
And that keeps going.
02:00
We can go all the way to our nth term and write it as x over 2 to the nth.
02:09
But we don't have quite what we want...