00:01
Hi, today we are solving the question in which we are given with the equation y double dash minus x into y is equals to zero.
00:09
We need to find a series solution around x naught is equals to zero for this ordinary differential equation second order.
00:18
So, we can see that here the power series solution is of the form yx is equals to summation of series from n is equals to zero till infinity an into xn.
00:35
Substituting this into the differential equation we get summation of series from n is equals to 2 till infinity n into n minus 1 an xn minus 2 minus x.
01:01
So, from here we get summation from n is equals to zero till infinity an xn is equals to zero.
01:11
We need to make sure that the series converges for all x.
01:16
So, to do this we can use ratio test.
01:21
So, from here an plus 1 by xn plus 1 by an divided by x is equals to n plus 1 into n into x an by an plus 1 divided by an.
01:55
So, from here we get as n tends to infinity the series converges limit of the absolute value of the ratio is less than 1 for all x...