- #1
Illuminerdi
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I understand most of the problem, but have yet to understand where a particular term came from. The problem is as follows:
Show that (0 to ∞)∫dx/[(x2+1)√x] = π/√2
Hint: f(z)=z−1/2/(z2+ 1) = e(−1/2) log z /(z2+ 1).
I actually have a solutions manual on me, but it's missing a step that I do not understand. I know to break the integral into 4 parts, an outer semi-circle contour that's infinitely large (of radius R), an inner contour that's infinitely small surrounding z=0 (of radius δ), a left contour from -R to δ, and a right contour from δ to R, but the solutions manual goes from parametrizing the left and right curves (by r) to combining them into a single integral with a factored term,
{δ to R} (1-i)∫dr/[(r2+1)√r].
I have no idea where this (1-i) term comes from.
Homework Statement
Show that (0 to ∞)∫dx/[(x2+1)√x] = π/√2
Hint: f(z)=z−1/2/(z2+ 1) = e(−1/2) log z /(z2+ 1).
The Attempt at a Solution
I actually have a solutions manual on me, but it's missing a step that I do not understand. I know to break the integral into 4 parts, an outer semi-circle contour that's infinitely large (of radius R), an inner contour that's infinitely small surrounding z=0 (of radius δ), a left contour from -R to δ, and a right contour from δ to R, but the solutions manual goes from parametrizing the left and right curves (by r) to combining them into a single integral with a factored term,
{δ to R} (1-i)∫dr/[(r2+1)√r].
I have no idea where this (1-i) term comes from.
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