Exercise 4 Direct or iterative? [15pt). Given the integer n > 2, consider the following system of linear equations: 3x1 - x2 = 1 Xi1 + 3x Xi+1 = 1, Xn-1 + 3xn = 1 Vi = 2, n - 1 (4) As explained in class, the complexity of Gaussian elimination is O(n3). Sketch this system of linear equations in a matrix form. For which n does Jacobi's method become competitive compared to Gaussian elimination for a tolerance = 10-3? And Gauss-Seidel's method? Exercise 4 Direct or iterative? [15pt). Given the integer n > 2, consider the following system of linear equations: 3x1 - x2 = 1 Xi1 + 3x Xi+1 = 1, Xn-1 + 3xn = 1 Vi = 2, n - 1 (4) As explained in class, the complexity of Gaussian elimination is O(n3). Sketch this system of linear equations in a matrix form. For which n does Jacobi's method become competitive compared to Gaussian elimination for a tolerance = 10-3? And Gauss-Seidel's method