Question

Hello! This is my first question ever. I am in AP Calculus and am working on a redo. I know the correct answer but don't know how to arrive at the correct answer. Attached is the question and answer choices. Thank you for your help!

Answer 1

Since
`\Delta x=\frac{b-a}n`, and you have a corresponding term in the given Riemann sum of
`\frac5n`, you know the integral is being taken over an interval of length 5, so you can omit the second choice.

Next,
`f(a+i\Delta x)` corresponds to
`a=3` with
`\Delta x=\frac5n`. The fact that
`a=3` alone tells you that the interval of integration starts at 3, and since we know the interval has length 5, that leaves the first choice as the correct answer.