00:01
Ok, so before we get started with the solution of this exercise, let me make a remark.
00:07
Well, the remark is the following.
00:09
The power series of expansion for tangent to the negative one of x is given by a sum with n running from zero up to infinity of negative one to the n multiplied by x to the 2n plus one over 2n plus one.
00:33
We are going to use this fact to find the power series expansion of our function f of x.
00:41
Well, at this point this is very easy.
00:45
The power series expansion for f of x is going to be a sum with n running from zero up to infinity of negative one to the n, perfect, multiplied by, ok, now we are going to have 5 to the 2n plus one over 2n plus one multiplied by x to the 2n plus one, perfect.
01:22
So this is part b of our exercise.
01:27
Well, for part a, what are the first three non -zero terms? well, here we are going to have the term associated to n equal to zero.
01:40
So we are going to have 5 multiplied by x.
01:46
This is the first non -zero term.
01:48
Oh, multiplied by, ok, negative one to the zero which is one, perfect...