Improper Integrals using Comparison method

peblez

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Jan 29, 2007
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Using the Comparison Theorem to determine if this integral is convergent or divergent.

[Int] from 0-->infinity [ x / ( x^3 + 1) ] dx

First i compare x^3 + 1 > x^3, thus x/(x^3+1) < x/x^3 = 1/x^2

But the integral of 1/x^2 can only be evaluated from 1 --> infinity. That integral is finite so it converges.

Thus the integral from 1--> infinity of [ x / (x^3 + 1)] dx converges. But the question asks for 0--> infinity.

So how do i know if the integral from 0--> 1 of [ x/ ( x^3 + 1 ) ] dx converges or not?
 
Ahhh nevermind. the integral from 0--1 is just a definite integral which means it must exist
 
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