Very hard area and definite integral problem
I'm lost on this stuff, can someone work this problem
Let f(x)= x^2 and compute the Riemann sum of f over the interval [2,4], using
a) Two subintervals of equal length (n=2).
b) Five subintervals of equal length (n=5).
c) Ten subintervals of equal length (n=10).
in each case, choose the representative points to be the midpoints of the subintervals.
d) can you guess at the area of the region under the graph of f on the interval [2,4]?
Repeat excercise above, choosing the reresentative points to be the right endpoints of the subintervals.