Complex Integration: Integrating x^0.5/(1+x^2)

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SUMMARY

The discussion focuses on the integration of the function x^0.5/(1+x^2) using complex integration techniques, specifically the residue theorem. The integral is expressed as ∫_0^{∞} (√x)/(1+x^2) dx. A suggested method involves using a half-disc contour in the upper half-plane, with considerations for the branch-point at the origin. The final result is derived from the integral over the real axis, equating to 2πi times the residue at the pole i.

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hedipaldi
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Homework Statement


integrate x^0.5/(1+x^2) by using complex integration


Homework Equations



residue theorem

The Attempt at a Solution


my attempt at a solution is attached.i need help in finding where am i mistaken.
thank's
Hedi
 

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. . . that's too messy to read. For me at least. Try and learn the math formatting language Latex to nicely format your math. Is this what you want to integrate:

[tex]\int_0^{\infty} \frac{\sqrt{x}}{1+x^2}dx[/tex]

If so, how about taking a half-disc contour in the upper half-plane, indented around the branch-point at the origin. For now, just suppose the small and large half-circle contours go to zero and you're left with the two legs on the real axis. Then the integral over those two legs is equal to 2pi i times the residue at i right.
 
Thank you, that works.
 

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