Numerical Method by Hornbeck Chapter-3, Problem 3.17 Find a forward difference expression of O(h) for d^6f/dx^6. Solution d6f/dx6 = D6 We know that - E = ehD ln E = hD D = (ln E) / h But, E = 1 + delta D = ln(1+delta) / h D6 = {ln(1+delta) / h}^6 d6f/dx6 = ln(1+delta) / h}^6 where, delta = forward difference operator.