The accuracy delivered by these methods is seen in the following error bounds. (Recall that the error bound is a bound on the absolute value of the difference between the actual area under the curve and its estimated value.)
For n intervals we express the error between the actual and
approximate area by 
. From page 306 of the text we have:
, M is the max value of
on 
.
, K is the max value of
on 
.