Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Limits Of Upper And Lower Sums

  1. Jun 20, 2012 #1
    I am currently reading about finding areas under graphs using summations, specifically taking the of the number of rectangles, n, goes to infinity. My books says that "because the same limit value is attained for both minimum value f(mi) and the maximum value f(Mi), it follows from the squeeze theorem that the choice of x in the ith sub-interval does not affect the limit." Why does the squeeze theorem say that I can do this?
  2. jcsd
  3. Jun 20, 2012 #2
    I suppose another way of wording my question is why can I choose any x-value in the sub-interval.
  4. Jun 20, 2012 #3
    Because f(mi)≤f(xi)≤f(Mi).

    Then summing, the middle sum is squeezed by the other two sums.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook