I'm working on using Riemann sums to find definite integrals. The answers aren't coming out as what they should be. Here's what I did. Sorry for all the stuff, but I'm trying to show as many steps as possible.

next I split the sums and distribute

4/n goes to zero, then I substitute in for each of the sums using formulas:

Integrating by using the antiderivative gives me:

Where did I go wrong?