Write a function file that determines the step size necessar

Write a function file that determines the step size necessary such that when the centered finite difference method is applied to find the derivative of the following function at x = 0.25 it achieves an absolute relative error to the exact value of 10^-6. e^x + x^2

Solution

e^x +x^2 = cosx + isinx + x^2

                 =cos(0.25) + isin(0.25) + (0.25)^2