What is the Integral of (2)/(x^2 + 1)?

  • Thread starter Thread starter ZedCar
  • Start date Start date
  • Tags Tags
    Integral
Click For Summary

Homework Help Overview

The discussion revolves around the integration of rational functions, specifically focusing on the integral of (2)/(x^2 + 1) and (2x)/(x^2 + 1). Participants explore the relationship between the integrals and their respective forms, questioning the correct application of integration techniques.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the integration of (2x)/(x^2 + 1) and compare it to the integration of (2)/(x^2 + 1), questioning the outcomes and the reasoning behind them. There is an exploration of whether the presence of 'x' in the numerator affects the integration process and results.

Discussion Status

Some participants have reached a consensus on the integral of (2x)/(x^2 + 1) and are now considering the implications of changing the numerator. There is an ongoing exploration of the integral of (2)/(x^2 + 1) and its relationship to known results, with participants sharing insights from computational tools.

Contextual Notes

Participants are navigating through the implications of different forms of the integral and the assumptions related to the presence of 'x' in the numerator. There is an acknowledgment of the need to clarify the integration techniques applicable to these forms.

ZedCar
Messages
353
Reaction score
1

Homework Statement



Integrate (2x)/(x^2 + 1)

Homework Equations





The Attempt at a Solution



Is the answer:

(2x) log|x^2 + 1|

as I thought the answer to this type of question is the log of the absolute value of the denominator multiplied by the numerator.

The answer given when I use Wolfram Alpha is log(x^2+1) + (tan x)^-1
 
Physics news on Phys.org
Actually your answer would be ln(x2+1)+C. (look at putting t=x2+1)

Which is what wolfram gave to me.
 
Thank you.
Yes, I'm getting the same answer as you now on Wolfram.

If the question had instead been
Integrate (2)/(x^2 + 1) (no x in the numerator)

Would the answer also have been log|x^2 + 1| + c
 
Oh, it's ok, I've just realized I can't do that.
 
ZedCar said:
Thank you.
Yes, I'm getting the same answer as you now on Wolfram.

If the question had instead been
Integrate (2)/(x^2 + 1) (no x in the numerator)

Would the answer also have been log|x^2 + 1| + c

In that case the answer would be 2tan-1(x) + C since d/dx(tan-1x) = 1/(x2+1).
 

Similar threads

  • · Replies 105 ·
4
Replies
105
Views
11K
Replies
3
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 6 ·
Replies
6
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 10 ·
Replies
10
Views
2K
  • · Replies 3 ·
Replies
3
Views
2K
Replies
10
Views
2K
Replies
5
Views
1K