Integration by parts, Partial fraction expansion, Improper Integrals

Click For Summary

Discussion Overview

The discussion revolves around integration techniques, specifically integration by parts, partial fraction expansion, and improper integrals. Participants are checking their calculations and discussing limits related to exponential functions.

Discussion Character

  • Homework-related

Main Points Raised

  • One participant checks their calculations for constants A, B, and C, suggesting A=2, B=$\frac{45}{21}$, and C=2, while expressing confusion over a limit calculation.
  • Another participant confirms A=2 but proposes B=3 and C=-2, while also providing a limit evaluation for $\lim_{{x}\to{\infty}}(e^{-x})$ and stating it equals 0.
  • There are repeated questions regarding the simplification of the fraction 0.25, with participants suggesting it can be expressed as $\frac{1}{4}$.

Areas of Agreement / Disagreement

Participants generally agree on the value of A but have differing views on the values of B and C. The discussion regarding the simplification of 0.25 also shows a lack of consensus on what constitutes simplest form.

Contextual Notes

There are unresolved mathematical steps regarding the values of B and C, as well as the simplification of 0.25. The limit calculation is presented without further context or assumptions.

ertagon2
Messages
36
Reaction score
0
View attachment 7785
  1. -
  2. check if right
  3. check if right
  4. Now, 2 seems to be the right answer for A yet when i made x=5 and subtracted new form form the old one I got a difference of ~$\frac{4}{9}$ (should be 0 obviously) I got A=2 B=$\frac{45}{21}$ C=2
  5. How to calculate $\lim_{{x}\to{\infty}}(- e^{-x})$
 

Attachments

  • mathsq2.png
    mathsq2.png
    6.3 KB · Views: 149
Physics news on Phys.org
2. Correct
3. Yes, notice that it's an odd function $f(-x)=-f(x)$ so the "areas" cancel out.
4. Might want to check your math here a bit. The answer is correct ($A=2$), but $B=3$ and $C=-2$.
Also, $\lim_{{x}\to{\infty}}(e^{-x})=\lim_{{x}\to{\infty}}1/e^x=0$ since the denominator goes to infinity.
 
Since when is 0.25 a fraction in simplest form?
 
Prove It said:
Since when is 0.25 a fraction in simplest form?

so =$\frac{1}{4}$ ?
 

Similar threads

  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 8 ·
Replies
8
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 21 ·
Replies
21
Views
4K
  • · Replies 14 ·
Replies
14
Views
3K
  • · Replies 11 ·
Replies
11
Views
2K
  • · Replies 19 ·
Replies
19
Views
4K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K