Integral Question (Riemann Sums)

Click For Summary

Homework Help Overview

The discussion revolves around a problem related to Riemann sums and integrals in the context of Single Variable Calculus. The original poster presents a two-part question involving the formulation of a Riemann sum and finding a specific Riemann integrable function.

Discussion Character

  • Exploratory, Mathematical reasoning, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to derive the general formula for the Riemann sum and is exploring the relationship between the Riemann sum and a specific function. Some participants suggest manipulating the expression by dividing the numerator and denominator by n² to facilitate the process.

Discussion Status

Participants are actively engaging with the problem, offering suggestions and clarifications. The original poster has made some progress but has not yet reached a complete solution. There is a collaborative effort to refine the approach and clarify expressions.

Contextual Notes

The problem is framed within the constraints of a final exam and involves specific requirements for the Riemann sum and the function to be found. The discussion reflects attempts to adhere to these constraints while exploring potential solutions.

altcmdesc
Messages
64
Reaction score
0
This is from a final exam on the MIT Open Course Ware site for Single Variable Calculus

Homework Statement



(a)(5 points) Write down the general formula for the Riemann sum approximating the Riemann integral,

1
\int f(x)dx
0

for the partition of [0,1] into n subintervals of equal length. Evaluate the function at the right endpoints of the subintervals.

(b)(5 points) Find a Riemann integrable function f(x) on the interval [0, 1] such that the formula for the Riemann sum from (a) equals the following formula,

n
\sum \frac{k}{k^{2}+n^{2}}
k=1

Show all work.


The Attempt at a Solution



I've figured out a) to be:

n
\sum \frac{f(k/n)}{n}
k=1

Using this result, on b) I get as far as:

f(k/n)=\frac{kn}{k^{2}+n^{2}}

But I can't get any farther.
 
Physics news on Phys.org
Divide the numerator and denominator by n^2. I.e. try to write the expression using only k/n.
 
Ah, I get it. x/(x2-1). Thanks
 
altcmdesc said:
Ah, I get it. x/(x2-1). Thanks

Um, x/(x^2+1), right? You're welcome.
 

Similar threads

  • · Replies 14 ·
Replies
14
Views
2K
  • · Replies 4 ·
Replies
4
Views
1K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 21 ·
Replies
21
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K