Given a smooth function / such that f(-0.2) = -0.91736, f(0) = -1 and f(0.2) = -1.04277. Using the 2-point forward difference formula to calculate an approximated value of f'(0) with h = 0.2, we obtain: f'(0) = -0.21385 f'(0) = -1.802 f'(o) -2.87073 f'(0) = -0.9802
