Integrating dx/sqrt(x^2+r^2) - Step-by-Step Guide

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    Integral
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Discussion Overview

The discussion revolves around the integration of the expression dx/sqrt(x^2+r^2). Participants seek a step-by-step guide to solve the integral, exploring various substitution methods.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant requests a detailed solution for the integral dx/sqrt(x^2+r^2).
  • Another suggests a substitution x=ru to simplify the integrand.
  • A participant reports simplifying the integral to du/sqrt(u^2+1) but expresses difficulty in proceeding further.
  • Alternative substitution methods are proposed, including x = r * sinh(u) and x = r * tan(u).
  • One participant expresses a preference for the trigonometric substitution due to discomfort with hyperbolic functions.
  • A later reply indicates success with the substitution x = r * tan(u) and achieving the desired result.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the best substitution method, as different approaches are suggested and one participant successfully applies a method while others express uncertainty.

Contextual Notes

Some participants may have varying levels of familiarity with hyperbolic functions and trigonometric substitutions, which could affect their understanding and preferences in solving the integral.

omer21
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how can i integrate this expression

dx/sqrt(x^2+r^2)

in books i found just the answer,but i need the solution step by step

can you help me?
 
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Now, let x=ru, where u is your new variable.

Try and simplify after this substitution of variables what you get as your integrand!
 
after simplifying i got this

du/sqrt(u^2+1)

but still i can not see the solution
 
If you don't recognize that integral, another useful substitution might be: x = r * sinh(u). Or, if you're unfamiliar with the hyperbolic functions, try the trigonometric substitution: x = r * tan(u).
 
Last edited:
hyperbolic functions are a little complicated for me so i will try x=r*tan(u)
 
That's the more difficult substitution, but alright!
 
i tried x=r.tan(u) substitution and i got what i want.
thanks...
 

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