Question about error theorem for simpsons rule

[badtwistoffate]

it is:
E=|I-Sn|>= (k4 (b-a)^2 )/ (180 n^4)

I know what all of the parameters mean except I, what is it again? It can't be the integral as that's why were using simpsons rule so is it a guess or?

 

[CarlB]

It is, in fact, the integral. Just because you don't know what it is doesn't mean you can't write an equation about it. S_n is the "n" guess.

Carl