Convergence of the following integral

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SUMMARY

The integral ∫ ln(x) dx / (√[3]{x}(x+1)) from 1 to ∞ is under investigation for convergence or divergence. The user seeks a comparison function g(x) that either converges or diverges to establish the behavior of the original function f(x). A suggested comparison function is g(x) = ln(x) / x^(4/3), and the user is exploring methods to determine its convergence without resorting to integration by parts.

PREREQUISITES
  • Understanding of improper integrals and convergence tests
  • Familiarity with logarithmic functions and their properties
  • Knowledge of comparison tests for integrals
  • Basic calculus techniques, including integration by parts
NEXT STEPS
  • Research the convergence of ∫ ln(x) / x^(4/3) dx using the Limit Comparison Test
  • Study the properties of logarithmic growth compared to polynomial decay
  • Learn about the Integral Test for convergence of improper integrals
  • Explore alternative comparison functions for integrals involving logarithmic terms
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Mathematicians, calculus students, and anyone studying improper integrals and convergence tests.

Dell
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i need to prove that the following converges or diverges

\int\frac{ln(x)dx}{\sqrt[3]{x}(x+1)} (from 1-∞)

what i have been trying to do is find a function that is either:
g(x)>f(x); g(x) converges
g(x)<f(x); g(x) diverges

but i have not been able,
is there any other way to solve this, or could you please show me a similar function that is one of the 2, if possible could you show how you reached your g(x)

thank you
 
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Hi Dell! :smile:

have you tried ∫ ln(x)/x4/3 dx ?
 
i thought of that, but what do i know about ln(x)/x^4/3, i would ideally liked to have taken it as my gx and said lim fx/gx=1 therefore f(x) behaves like ln(x)/x^4/3, how can i fin out if ln(x)/x^4/3 converges/diverges, do i have to integrate it? if so is there a simpler way than integration in parts? if not, is there not a simpler function you can think of
 
Dell said:
how can i fin out if ln(x)/x^4/3 converges/diverges, do i have to integrate it?

D'uh! :rolleyes:

you'd think so, wouldn't you?

get on with it!
 

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