Integrating Green's function and plotting.

asked 2017-05-06 18:02:05 +0200

quackee gravatar image

updated 2017-08-01 19:10:17 +0200

FrédéricC gravatar image

Hi, I am trying to integrate product of two Green's functions and plot the results using Maxima. The problem is that Green's functions have singularities.

$ I=\int_{-\infty}^{+\infty}dxG1(x)G2(x)(F1(x)-F2(x))$


$ G1(x) = \frac{1}{ (x-0.1)+0.5+0.00001i} $

$ G2(x) = \frac{1}{ (x-0.1)+0.5-0.00001i} $

$ F1(x) = \frac{1}{ 1+e^{\frac{x}{0.2}}}$

$ F2(x) = \frac{1}{ 1+e^{\frac{x+0.4}{0.2}}}$

When I use wxMaxima (CAS), it fails to integrate and it fails to plot the solution y. I know that the solution plot should look like a smoothed step function where rising edge should be at x=0.1.

Any suggestions how to code wxMaxima is appreciated.

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Just a note that this forum is for Sage stuff; you may not find many wxMaxima experts here.

kcrisman gravatar imagekcrisman ( 2017-05-06 23:03:01 +0200 )edit