Write a new Matlab code $($Code $6)$ for the following form of the one$-$dimensional linear

steady$-$state advection$-$diffusion equation:

$U\frac{df}{dx}-D\frac{d^{2}f}{d{x}^2}=s(x),$ where $s(x)$ is a known source.

using the method of Gauss$-$Seidel successive over$-$relaxations.

a$)$ Re$-$run the problems shown in Fig. $6\mathrm{.}5$ in Kundu et al$.$

b$)$ Run the cases in Fig. $6\mathrm{.}5$ with $s(x)=1.$

Submit the developed code and the plots created. Discuss the results.