Consider the following finite difference approximation for the base point (xi) in a one-dimensional finite difference domain
FDA =(2Fi - 5F(i+1) + 4F(i+2) - F(i+3)) / ( delta x^2)
where delta x is constant. Determine what this FDA is an approximation of, the order of the approximation, and the accompanying truncation error. Is this a forward, backward, or central difference?