Integration of irrational function

gruba
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Homework Statement


Find the integral \int \frac{1}{(x-2)^3\sqrt{3x^2-8x+5}}\mathrm dx

2. The attempt at a solution
I can't find a useful substitution to solve this integral.
I tried x-2=\frac{1}{u},x=\frac{1}{u}+2,dx=-\frac{1}{u^2}du that gives
\int \frac{1}{(x-2)^3\sqrt{3x^2-8x+5}}\mathrm dx=-\int \frac{u}{\sqrt{3\left(\frac{1}{u}+2\right)^2-8\left(\frac{1}{u}+2\right)+5}}\mathrm du

Is there a useful substitution for u?
 
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gruba said:

Homework Statement


Find the integral \int \frac{1}{(x-2)^3\sqrt{3x^2-8x+5}}\mathrm dx

2. The attempt at a solution
I can't find a useful substitution to solve this integral.
I tried x-2=\frac{1}{u},x=\frac{1}{u}+2,dx=-\frac{1}{u^2}du that gives
\int \frac{1}{(x-2)^3\sqrt{3x^2-8x+5}}\mathrm dx=-\int \frac{u}{\sqrt{3\left(\frac{1}{u}+2\right)^2-8\left(\frac{1}{u}+2\right)+5}}\mathrm du

Is there a useful substitution for u?
Factor ##\ 3x^2-8x+5\ ##. Then putting your u substitution into that simplifies things a bit.
 
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There are two things I don't understand about this problem. First, when finding the nth root of a number, there should in theory be n solutions. However, the formula produces n+1 roots. Here is how. The first root is simply ##\left(r\right)^{\left(\frac{1}{n}\right)}##. Then you multiply this first root by n additional expressions given by the formula, as you go through k=0,1,...n-1. So you end up with n+1 roots, which cannot be correct. Let me illustrate what I mean. For this...
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