The following data show estimates of the population of Liberia in selected years between 1960 and 2010: Year 1960 1970 1980 1990 200 2010 Population(millions) 1.1 1.4 1.9 2.1 2.8 4 a) Use two-point backward difference formula. (10 POINTS) b) Use the three-point backward difference formula. (10 POINTS) Finite Difference Formulas First Derivative Method Formula f(Xi+1)-f(x) Truncation Error O(h) Two-point forward difference Three-point forward difference f'(x) = h -3f(x) + 4f(X+1)-f{Xi+2) = ('x),/ O(h) 2h f(x)-f(xi-1) f'(x) = Two-point backward difference Three-point backward difference Two-point central difference O(h) h f(Xi-2) 4f(Xt-1) + 3f(x;) f'(x) =D 2h f(Xi)-f(Xi-1) O(h) f'(x) = 2h