Real Analysis Riemann Integration

Click For Summary
The function f(x) is defined as 1 for 0 ≤ x ≤ 1 and 2 for 1 ≤ x ≤ 2. To show that f is Riemann integrable on [0, 2], partitions can be used, specifically Pe = {0, 1-(ε/2), 1+(ε/2), 2}. The upper sum U(f,P) equals 2, while the lower sum L(f,P) approximates to 2 - ε, leading to the difference U(f,P) - L(f,P) equating to ε. An alternative approach suggests using additivity of integrals, where the integral from 0 to 2 can be expressed as the sum of integrals from 0 to 1 and from 1 to 2, effectively addressing the issue at x=1. The function is confirmed to be Riemann integrable, and the value of the integral can be computed accordingly.
s23fsth
Messages
1
Reaction score
0
Suppose we have: f(x)= 1 if 0\leq x \leq 1 AND 2 if 1\leq x \leq 2
Using the definition, show that f is Riemann integrable on [0, 2] and find its value?

I have a general idea of how to complete this question using partitions and the L(f,P) U(f,P) definition, but am not quite receiving the answer I would like...

My workings, Fix \epsilon\succ 0 with partitions Pe = {0, 1-(\epsilon / 2), 1 + (\epsilon / 2), 2}. Then, if U(f,P)=2, we can define: L(f,P)=1(1-\epsilon/2)+1(1-\epsilon/2) = 2-\epsilon Then computing, U(f,P)-L(f,P)= 2-(2-\epsilon) =ε\precε

This doesn't seem right to me, and I am not quite sure what else to do? Any suggestions?
 
Physics news on Phys.org
You could simply use additivity: ##\int_0^2=\int_0^1+\int_1^2## and the problem at ##x=1## will be solved.
 

Similar threads

  • · Replies 16 ·
Replies
16
Views
4K
  • · Replies 3 ·
Replies
3
Views
3K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 23 ·
Replies
23
Views
4K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 10 ·
Replies
10
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 18 ·
Replies
18
Views
3K