Calc II: What is the I'th Subinterval?

[bmed90]

Hello, I've been in calc II for awhile and for some reason I cannot grasp the concept of what is ment by the ith subinterval. I know it has to do with summing up n number of slices. Can anyone please elaborate? Maybe have a simple explanation for what the ith subinterval is ? Thanks

 

[HallsofIvy]

I suspect you are talking about the Riemann integral. To define the integral on some interval [a, b], you divide it into n "subintervals". If you then number them 1, 2, 3, ..., from, say, left to right, you have the "first subinterval", the "second subinterval", etc. The "ith subinterval" is just the subinterval that is numbered "i".