I do not understand the final step taken to solve this problem (It was an example given in class) I would really appreciate it if someone would be able to explain the simplification process for the final step?
f(x) = x^{n}
for
n ≥ 0, [0, 2]
=
I understand that one must solve using the given limits, which would give me a value of:

However, I am not following the what happens in order to have the final solution of:
I end up with my final solution being:
Any sort of help is greatly appreciated! Thank you