Change to cartesian double integral to polar coordinates and evaluate

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SUMMARY

The discussion focuses on evaluating the double integral of the function 1/((1+x^2+y^2)^2) over the first quadrant, specifically from 0 to infinity for both x and y. The transformation to polar coordinates is applied, leading to the integral ∫(0 to π/2) ∫(0 to ∞) (1/(1+r^2)^2) r dr dθ. The limits for θ are established as 0 to π/2, reflecting the first quadrant. A substitution s=(1+r^2) is suggested to simplify the evaluation process.

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Homework Statement



integrate 1/((1+x^2+y^2)^2) dx dy Both x and y going from 0 to infinity

Homework Equations



x^2+y^2 =r

The Attempt at a Solution



After that I get 1/(1+r^2) ^2

Cannot visualize the function, do not know what the limits are.

If I could have any help it would be greatly appreciated
 
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After the substitution you have:
\int_{0}^{\frac{\pi}{2}} \int_{0}^{\infty} \frac{1}{(1+r^2)^2} r dr d \theta
Imagine x and y both going from zero to infinity. They span the whole first quadrant and therefore theta goes from 0 to pi/2.
After this, try the substitution s=(1+r^2).
 

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