Examine the Riemann sum at right for the area under
How many rectangles were used?
Notice that the index starts at
and ends at .
If the area being approximated is over the interval
, what are the values of and ?
General form of a left endpoint Riemann sum:
is easy to spot in the Riemann sum. Now determine the end value, .
, so each rectangle has a width of .
You already computed how many rectangles there are part (a).