Given the function $f(x) = e^{-x^2}$, how can I find $f^{(n)}(0)$?
The Taylor series for $e^{-x^2}$ can be written by expanding $e^u$ where $u = -x^2$:
$$e^{-x^2} = \sum_{n=0}^{\infty} \frac{(-x^2)^n}{n!}$$
This simplifies to:
$$e^{-x^2} = \sum_{n=0}^{\infty} \frac{(-1)^n x^{2n}}{n!}$$
First of all, why can I simply plug in that $-x^2$and can I just diffrentiate it? but in order to diffrentiate it term by term I need the sum to converge uniformly to my function. Is it tho? I am not really sure what should I do.Any help will be appreciated!