Graph f + g.

L31 - 5 Summation Notation We use summation notation to write sums in compact form: ▯n ai= i=m ▯4 ex. i = i=1 ▯5 ex. (k − 1) = k=2 Now, we use summation notation to express the sum more concisely as A ≈ Generally, if f is continuous, as the number of subinter- vals gets larger and widths get smaller the approximation is closer to actual area. We can then deﬁne A =