4. Add the following two polynomial coefficient vectors by-hand, and verify using Matlab. P1 = x³ + 6x² + 11x + 6 and P2 = x² - 2x + 1. Plot the two polynomials on the same graph, for -5<x<3. Utilize the polyval command. Label the x-axis "x", the y-axis "P1, P2". Use "Plot of two polynomials" as title for your plot. Show the grid.

Fig: 1