For your first interval, you must go to the midpoint of the first rectangle.

Since our interval is (5-2)/10=3/10, we must go to 3/20 for the first one and then add 3/10 successively.

2+3/20=43/20

43/20+3/10=49/20

Then keep adding 3/10 until you get to the end, which will be 4.85(the midpoint of the last rectangle).

11/4

61/20

67/20

73/20

79/20

17/4

91/20

97/20

Now, enter these values into what is to be integrated.

and so forth.

Then add them all up and multiply by 3/10. You should get something close to the actual integral, which is 14/3=4.667

I would show you a nice graph of it, but I can't get my Maple 10 to work on this infernal Vista. It is incompatible.