Understanding Improper Integrals with Limits at Infinity

Click For Summary
The discussion focuses on evaluating the improper integral of the function 2/(x^2 + 4) from negative infinity to 2. The user attempted to split the integral into two parts but encountered difficulties with the limits and integration process. There is confusion regarding the correct approach to take when setting the approaching variables for the limits at infinity. Additionally, there is a misconception about the integral of the function, as it is not related to the natural logarithm. Clarification on these points is needed to properly solve the integral.
sinequanon
Messages
6
Reaction score
0

Homework Statement



\int(2dx/(x^2+4)
from x= -\infty to x=2

Homework Equations



No specific ones.

The Attempt at a Solution



So, from there I tried to split the integral into two, integrating between 2 and -2, and -2 and -\infty, but I got very lost trying to take the limits for these, partly because I don't know what to set as the approaching variables in each case. And integrating the function actually is another issue. Could someone take a look?
 
Last edited:
Physics news on Phys.org
I think you need to integrate that over.

\int \frac{1}{x^2+4} \neq lnG(x)
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

Similar threads

  • · Replies 7 ·
Replies
7
Views
2K
Replies
2
Views
2K
  • · Replies 9 ·
Replies
9
Views
2K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 13 ·
Replies
13
Views
3K
  • · Replies 5 ·
Replies
5
Views
1K
  • · Replies 16 ·
Replies
16
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K