I would be grateful if you could explain it without "Big O" notation, or if easier you could explain the "Big O" notation.
I understand that is a function that is not important in finding the answer, written to simplfy things.
In this is case it depends on 1/n^2, so I supouse it goes to 0 when n-> infinity.
And we apply it for a=0:
for x between [0,1].
I haven't studied Taylor's Theorem (or formula) at school, so I don't know if I had applied correctly.
Assuming what have I written is correct, I understood everything. Again I thank you very much.