How to integrate sqrt((ax+b)/x) dx (square root of linear fractional function)

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Discussion Overview

The discussion revolves around the integration of the function sqrt((ax+b)/x) dx, where a and b are constants and x is a variable. Participants explore various methods and approaches to tackle this integral, with a focus on specific conditions where a and b are both greater than zero.

Discussion Character

  • Mathematical reasoning
  • Exploratory
  • Homework-related

Main Points Raised

  • One participant poses the initial question about how to integrate sqrt((ax+b)/x) dx, specifically requesting solutions under the condition that a and b are both greater than zero.
  • Another participant suggests a substitution method, letting u = (ax+b)/x, and proposes further simplification by letting v = sqrt(u) to facilitate integration.
  • A third participant reiterates the original question and introduces a different substitution, x = (b/a)(sinh(t))², indicating an alternative approach to the problem.
  • One participant recommends using an online integral calculator, directing others to input the function into a specific website for assistance.

Areas of Agreement / Disagreement

There is no consensus on a definitive method for solving the integral, as participants propose different approaches and substitutions without agreeing on a single solution.

Contextual Notes

The discussion includes various assumptions about the constants a and b, and the effectiveness of the proposed methods remains unverified. The mathematical steps involved in the suggested substitutions are not fully resolved.

Holali
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Hi,
simple question, but difficult to find an answer for me

How to integrate sqrt((ax+b)/x) dx ?
a,b constants and x variable

if it matters, I would be happy if you could solve it just for both a,b >0

Thanks
 
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Let u=\frac{ax+b}{x}. We're keeping our fingers crossed, there's no other common methods that apply, so this looked like most natural thing to do.

The expression will be a little simpler, but now we try a more common method, which is let v=\sqrt{u}. To find du, we usually consider v^2=u, to simplify things. I think you will end up with something that you know how to integrate.
 
Holali said:
Hi,
simple question, but difficult to find an answer for me

How to integrate sqrt((ax+b)/x) dx ?
a,b constants and x variable

if it matters, I would be happy if you could solve it just for both a,b >0

Thanks

Let x = (b/a)(sinh(t))²
 
go here:


integrals.wolfram.com/index.jsp

and enter

sqrt[(a*x+b)/x]

into the text box
 

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