# Revision history [back]

### Integrating Green's function and plotting.

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.

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

and

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

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

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

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

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.

 2 retagged FrédéricC 5114 ●3 ●42 ●111

### Integrating Green's function and plotting.

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.

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

and

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

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

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

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

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.