Past exam of the year 1 of the computer science course of the University of Oxford / 2017 / Digital systems, linear algebra, introduction to formal proof / 6 / b / ii

As $x_0=0$, solve $(D-L)x_1=b$. Its first row gives $4(x_1{)}_1=1$; its second gives $(x_1{)}_1+2(x_1{)}_2=-1$. ThereforeThe second component uses the new first component $1/4$, distinguishing Gauss-Seidel iteration from Jacobi iteration.