Integral by Parts: Solving 2 Integrals Involving Arctg(x) & Sqrt(1-x^2)

In summary, the conversation suggests using the MacLaurin expansion to integrate the given function, but the approach may not be suitable for students who have not studied series yet. The conversation ends with a request for an alternative solution without using series.
  • #1
leprofece
241
0
integral of arctg(x)/sqrt(1-x^2)

maybe u = arctg x du = 1 /1+x^2
but x = tg u
maybe this is the way isn't it?
 
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  • #2
Wolfram couldn't find an antiderivative so I doubt there is one...
 
  • #3
leprofece said:
integral of arctg(x)/sqrt(1-x^2)

maybe u = arctg x du = 1 /1+x^2
but x = tg u
maybe this is the way isn't it?

A possible approach is to use the MacLaurin expansion...

$\displaystyle \frac{\tan^{-1} x}{\sqrt{1-x^{2}}} = x + \frac{1}{6}\ x^{3} + \frac{49}{120}\ x^{5} + \frac{81}{560}\ x^{7} + \mathcal{O}\ (x^{9})\ (1)$

... and to integrate term by term...

Kind regards

$\chi$ $\sigma$
 
  • #4
chisigma said:
A possible approach is to use the MacLaurin expansion...

$\displaystyle \frac{\tan^{-1} x}{\sqrt{1-x^{2}}} = x + \frac{1}{6}\ x^{3} + \frac{49}{120}\ x^{5} + \frac{81}{560}\ x^{7} + \mathcal{O}\ (x^{9})\ (1)$

... and to integrate term by term...

Kind regards $\chi$ $\sigma$

Thank for your answer but you must solve it by normal or traditional methods students have not studied series yet
Could anybody do that way??
 
  • #5
leprofece said:
Thank for your answer but you must solve it by normal or traditional methods students have not studied series yet
Could anybody do that way??

Hey! :D

As with your other recent thread - for \(\displaystyle \int \sqrt{x}e^x\, dx\) - it sounds like your teacher is asking you to do stuff without him or her teaching you the things necessary to solve the problem... (Headbang)
 

FAQ: Integral by Parts: Solving 2 Integrals Involving Arctg(x) & Sqrt(1-x^2)

1. What is the formula for solving integrals using integration by parts?

The formula for solving integrals using integration by parts is ∫u dv = uv - ∫v du, where u and v are functions of x and dv and du are their respective differentials.

2. How do I determine which function to choose as u and which to choose as dv?

When using integration by parts, the mnemonic "LIATE" (Logarithmic, Inverse trigonometric, Algebraic, Trigonometric, Exponential) can be helpful in determining which function to choose as u. The function that comes first in the order should be chosen as u.

3. Can I use integration by parts on any type of integral?

Integration by parts can be used on any integral, but it may not always lead to a simpler solution. It is best used when one function is easy to integrate and the other is easy to differentiate.

4. How do I solve integrals involving arctangent and square root functions?

When solving integrals involving arctangent and square root functions, it is helpful to use the substitution method to simplify the integral before applying integration by parts. For example, substituting x = sinθ can simplify integrals involving arctangent.

5. Are there any specific rules for choosing u and v when solving integrals involving arctangent and square root functions?

There are no specific rules for choosing u and v when solving integrals involving arctangent and square root functions. It may require some trial and error to determine the best choice for u and v, but generally, choosing the more complicated function as u can lead to a simpler solution.

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