[QUOTE=alteraus;794113]Hi there, I am trying to find the Maclaurin expansion of 3rd degree of the function but I get strange result ..
I need to ask what am I doing wrong ..
I started with
where for there holds ...
This is, at least, one problem: the first two terms should be , not .
then I substituted and I got
after that I used the Maclaurin expansion of and I got
but the result should be
where's the mistake then?
thanks for any help