**in Matlab. please give description for lines of code

4.7 Use forward and backward difference approximations of Oh) and a centered difference approximation of Och to estimate the first derivative of the function examined in Prob. 4.5. Evaluate the derivative at x = 2 using a step size of h = 0.2. Compare your results with the true value of the derivative. Interpret your results on the basis of the remainder term of the Taylor series expansion. 49 TL