I came across this question:
What's the domain of $f(x)=\int (x+2x^2+3x^3+\dots) dx$?
I think it'd be a polynomial, something like $\frac{x^2}{2}+\frac{2x^3}{3}+\dots$, which domain is all real numbers ($\mathbb R$) but it's not correct according to the book. I'm stuck.
EDIT:
The answer should be one of the followings:
- $(-1,1)$
- $(-1,1]$
- $[-1,1)$
- $[-1,1]$