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

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

The integral of (2)/(x^2 + 1) results in 2tan-1(x) + C, as confirmed by multiple users in the discussion. The confusion arose from the integration of (2x)/(x^2 + 1), which leads to ln(x^2 + 1) + C. Users referenced Wolfram Alpha for verification, which provided consistent results for both integrals. The discussion highlights the importance of recognizing the role of the numerator in determining the integration technique.

PREREQUISITES
  • Understanding of basic calculus concepts, specifically integration.
  • Familiarity with logarithmic and inverse trigonometric functions.
  • Knowledge of the properties of derivatives, particularly d/dx(tan-1(x)).
  • Experience using computational tools like Wolfram Alpha for verification of mathematical solutions.
NEXT STEPS
  • Study integration techniques involving rational functions.
  • Learn about the properties and applications of inverse trigonometric functions.
  • Explore the use of Wolfram Alpha for solving calculus problems.
  • Practice integrating various forms of functions to solidify understanding of integration rules.
USEFUL FOR

Students studying calculus, mathematics educators, and anyone seeking to improve their skills in integration techniques and verification methods using computational tools.

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
3
Views
2K
  • · Replies 105 ·
4
Replies
105
Views
7K
  • · 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
952