Write Matlab code for the finite difference method of this linear combination.

I wrote this code and my answers are coming out wrong, and i can't find examples for this type online. Help please and thank you

Consider the following first-order finite-difference methods for solving u = ??-??3 (where u-u(t), ? and ? are parameters): 2 n+1 Show whether or not the linear combination, Mi + 3M2 - 2M3, is second-order ac- curate. Analyse the stability of the fixed-points of the method. Does the method undergo period-doubling oscillations? Carry out simulations, using step-sizes h 1,1,5,10,100, to illustrate your theoretical results 10 points Consider the following first-order finite-difference methods for solving u = ??-??3 (where u-u(t), ? and ? are parameters): 2 n+1 Show whether or not the linear combination, Mi + 3M2 - 2M3, is second-order ac- curate. Analyse the stability of the fixed-points of the method. Does the method undergo period-doubling oscillations? Carry out simulations, using step-sizes h 1,1,5,10,100, to illustrate your theoretical results 10 points