choice of method: set c=0 for left-hand sum, c=1 for right-hand sum, c=0.5 for midpoint sum
10
運算式 11: "c" equals 1c=1
11
Integral approximation
12
運算式 13: "I" equals Start sum from "i" equals 0 to "n" negative 1, end sum, "f" left parenthesis, "s" left parenthesis, "i" , right parenthesis , right parenthesis times "w"I=n−1∑i=0fsi·w
