1 (25 points). Use finite difference method to approximate solutions to the nonlinear boundary value problems for n = 10. Y" = 18y2 y(1) = 1/3 y(2) = 1/12 (a) Give the finite difference method to solve the boundary value problem and the Matlab codes. (b) Plot the approximate solutions, and compare with the exact solution y=1/(3). Take n = 20 and 40, and plot the errors of the numerical solution over the grid points