00:01
In this question, we are asked to find the radius of convergence and the interval of convergence of the following series.
00:07
To do that, we're going to use the ratio test.
00:14
By the ratio test, we first need to calculate the limit of absolute value of an plus 1 over an as n goes to infinity.
00:25
Here, a .n is a general term of the series.
00:30
In our case, this is going to be limit, absolute value of...
00:34
Now we need to replace n by n plus 1 everywhere.
00:38
We're going to get 2 n plus 2 factorial times x to the n plus 1 divided by 2 to the n plus 1.
00:50
Multiply by the reciprocal of a .n, which is going to be 2 to the n over 2n factorial times x to the n.
01:06
This is equal to the limit, absolute value, of x times 1⁄2...