00:01
We were asked to answer some questions about sequences generated by newton's method.
00:08
So, the newton's method applied to a differential function, f has a starting value x not and constructs a sequence of numbers, according to their recursion formula, xn plus 1 equals xn minus f of xn over f prime of xn.
00:31
And in part a, we're given a function, f, and we're asked to write their recursion formula.
00:51
So f of x equals x squared minus a, where a is greater than zero.
01:00
And so we have that their recursion formula can be calculated first.
01:06
We need to calculate the derivative.
01:08
So the derivative of f is 2x.
01:13
And so we have their accursion formula for f.
01:16
It's going to be xn plus 1 equals xn minus, x n squared minus a over to x n and this can be rewritten as the factor out or if we divide we get xn minus this becomes xn over 2 plus a over 2 xn and this is equal to after adding like terms we get 1 half x n plus a over 2 x n and this is equal to after adding like terms we get 1 half x n plus a over 2 xn, which can be written as xn plus a over xn divided by 2.
02:52
And in part b, we're given values for the first term of the sequence and a.
02:59
And we're asked to calculate successive terms until the display repeats.
03:08
So we have that the first term is going to be 1, and that a is going to be 3.
03:19
And so by the previous part, we have the recurrence relation is xn plus 1 equals xn plus 3 over xn divided by 2.
03:41
And so we have that x0 is as we're given 1...